DatabaseProgramming.pdf

TABLE OF CONTENTS

CHAPTER 1: INTRODUCTION TO DATABASE AND MICROSOFT ACCESS 2007 ........................ 2

1.1 Relational Database Elements............................................................................................................ 3

1.2 Relationship within a Database .......................................................................................................... 5

1.3 Database Management System (DBMS) ............................................................................................ 6

1.4 Introduction to Access 2007 ............................................................................................................... 7

CHAPTER 2 : STRUCTURED QUERY LANGUAGE ........................................................................... 13

2.1 SQL Data Types ................................................................................................................................. 15

2.2 SQL as Data Definition Language .................................................................................................... 15

2.3 SQL as Data Manipulation Language .............................................................................................. 17

2.4 SQL as Data Query Language .......................................................................................................... 19

CHAPTER 3: DATABASE PROGRAMMING USING OLEDB TECHNIQUE ..................................... 26

3.1 Database Connectivity ...................................................................................................................... 27

3.2 Database Manipulation & Query ....................................................................................................... 33

CHAPTER 4: DATABASE PROGRAMMING USING ADODB TECHNIQUE .................................... 58

4.1 Step 1 : Creating the database ......................................................................................................... 59

4.2 Step 2 : Designing application interface ......................................................................................... 61

4.3 Step 3 : Adding project components ............................................................................................... 66

4.4 Step 4 : Variable declaration............................................................................................................. 67

4.5 Step 5 : Connection String & Data Source ...................................................................................... 68

4.6 Step 6 : Connection State ................................................................................................................. 68

4.7 Step 7 : Form Code ............................................................................................................................ 69

CHAPTER 5: DATA REPORTING USING REPORT VIEWER .......................................................... 79

5.0 DATA REPORTING USING REPORT VIEWER ............................................................................. 80

5.1 Creating DataSet ................................................................................................................................ 80

5.2 Creating Report ................................................................................................................................. 82

5.3 Creating Microsoft Report Viewer .................................................................................................... 90

Database Programming Using Access 2007 & Visual Studio 2008

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CHAPTER 1:

INTRODUCTION TO

DATABASE AND

MICROSOFT ACCESS

2007

After you have completed this

chapter, you should be able to :

Define the basic

definition of database

and relational

database elements

Explain three types of

relationship in

relational database

and know how to

create relationship

within a database

Explain the basics of

database

management

software (DBMS)


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1.0 INTRODUCTION TO DATABASE & MICROSOFT ACCESS 2007

atabase is an integrated collection of related files, records and data. It also can be defined as an

organized collection of data in an integrated place where it can be accessed and managed

systematically and can be accessed by multiple users at the same time. Database is a unique

concept on how to manage data structures in an organized and integrated fashion.

One of the most popular databases handling method today is relational database system. Relational

database handles all data in a tabular form. All information is being kept in a table that consist of columns

and rows.

Below are the important elements of a relational database model:

1.1 Relational Database Elements

a. Table

Table is considered as the main building block of a database. It is a set of data elements which

is organized in columns and rows. Each column represents an attribute which is called field.

Examples of tables are Student, Employee, Sales, Purchase and Subject.

b. Field

Column in table is also called as field. Each field has a distinct name and is used to store

different element of a data. Each field will have different type of data format. Examples of field

are Student_Name, Student_Matric, Student_Address, Employee_Status, Sales_Date and

many others.

c. Record

Table row represents data value for an item. Each row has its own data value and is referred

as record in tables. Examples of record are ‘10111’, ‘10113’ for Student_Matric field,

‘Ali’,’Rajinikanth’ and ‘Andy Lau’ for Student_Names

d. Keys

A key is an attribute (field) that determine other attributes. It is used to uniquely identify each

record in database tables. Keys are also important because it is used to establish relationship

between tables and to ensure the integrity of the data. Examples of keys are Student_Matric

for Student table, Employee_ID for Employee table and Sales_ID for Sales table.

D

Record

Field/Column

Figure 1: Table Example


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Keys can be divided to primary key, foreign key, superkey, candidate key and secondary keys,

however, in this topic the discussion will only be limited to primary key and foreign key only.

Primary key is the main key in table to uniquely identify each record. Normally it comprises of

single field, but there are cases which primary key comprises of more than two fields.

Foreign key is the key used in defining relationship between tables. It is the primary key from

the referenced master table. The value between the two related fields must match each other.

A table can have many foreign key, depending on the table which it related to.

In the example above, Department_Code and Manager_ID is the primary key in the table

Department and table Manager. While in the table Manager, Department_Code act as the

foreign key. The concept of relationship between entities and tables will be explained in detail

in the topic Relationship within a Database.

Figure 2: Primary and Foreign Key Example


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1.2 Relationship within a Database

a. 1 : 1 (One To One)

1: 1 relationship rarely happens in database design. It happens when one entity is related with

only one other entity and the other way round. In this relationship only one occurrence of the

related record in the related tables happens.

Example of 1:1 relationship is the relation between Employee and Authentication. One

employee can own one authentication id only and one id can be owned by only one employee.

b. 1 : M (One To Many)

1:M relationship is the common relation that happen in relational database. This type of relation

happens when one record in the master table is related with many records in the child table. It

is linked by using foreign key in the child table. Note that the foreign key is the primary key

from the master table.

Example of 1: M relationship is the relationship between book and shelf. One book can be

located in only one shelf while one shelf can locate many books. Another example is between

Voucher and Cheque. One voucher can produce many cheques while one cheque can be

produced by only one voucher.

Figure 4: One To Many Relationship

Figure 3: One To One Relationship


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c. M : M (Many To Many)

M:M relationship refers to relation when many records also related with many records in the

related table. In the case of M:M relationship which can be implemented directly, an

intermediate entity has to be created. This intermediate entity will consist of primary key from

both of the related table and also other fields which are required in the relationship.

Example of many to many relationship is Student and Subject. One student can take many

subjects and in the same time one subject can be taken by many students. In this case,

intermediate entity has to be created. The name of the intermediate entity can be the

combination of the two tables or other names which are appropriate.

1.3 Database Management System (DBMS)

DBMS is a complex software programs that can be used to organize and manage a database. It

acts as middleware between users and database. The main function of DBMS are to create

database and its elements such as tables and index, define relationship between tables, perform

data retrieval and data query using query language, administer its users and security and produce

reports.

There are a lot of DBMS vendors in the market such as MySQL (open source), Oracle (Sun),

SQLServer (Microsoft), PostgreSQL (open source), DB2 (IBM) Informix (IBM) and many more.

Each type of DBMS has their own specialty and specific purposes, for example, IBM Informix is

Figure 5: Many To Many Relationship

Data Query

Relational

Database

Structure

End Users

End Users

DBMS (Database

Management System) End User Data Request

Figure 2: DBMS relates end user and database structure


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meant to focus on online transaction processing while MySQL is an open source database software

for middle size application.

One of the popular DBMS for students and small medium size organization that use Windows

platform is Access from Microsoft Corporation. Access is one of the software included in the

Microsoft Office suite and is highly used around the world because of its simplicity and friendly user

interface. In this book, Microsoft Access 2007 will be used as the main database.

1.4 Introduction to Access 2007

Microsoft Access is an application used to create small and midsize computer desktop databases

for Microsoft Windows family of operating systems. Starting with version 1.0 in 1992, Access DBMS

continue to expand with lots of new and exciting functionalities to manage database from time to

time. Figure below shows the evolution of Access from 1992 until now. The latest version of Access

comes in Microsoft Office 2007 suite and is also known as Access 2007.

The new version of Access 2007 uses different extension which is .accdb compared to prior version

which use .mdb. The new format enables Access to handles multi value and attachment in fields.

Access 2007 offers a totally different environment compared to previous version but it still maintains the

basic features of Access which are creating tables, queries, forms and reports by using design mode or

wizard. Advanced users can use and VBA (Visual Basic for Application) to enhance the Access

application.


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Besides the core function, there are lot more functionalities such as user administration, maintaining

securities, switchboard and many more. One of the major upgrade in Access 2007 is its interface where

it uses the ribbon concepts that contains iconic like toolbar to create database elements. Each icon has

its own functionalities.

In this module, you are going to create an Access 2007 file to store your data while Visual Basic 2008

will serve as the interface of your database system. The discussion of Access will only be limited to the

creation of tables because queries, form and report will be created by using Visual Basic 2008 and

crystal report.

1.4.1 Create New Database File.

1. Start Microsoft Access 2007

2. Click New Blank Database icon

3. Enter Sales as the file name to replace the default name (Database1).

4. Select the directory where you want to save your file by clicking the folder icon.

(The default directory is My Document folder) and click Create button.


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1.4.2 Creating Tables

Table is the most important components of any relational database. Data in database

is stored in tables in a form of columns and row. Table column represents the data

characteristics which is known as field while table rows represents data item and is

known as record.

To create a table, click table on the create tab. You can choose either to use the

normal table view or use table templates or straight away use table design which will

open the classic design mode.

When table had been created, it will appear in datasheet view. In this mode, you can

add delete or update fields, modify the formatting, set null properties, create a lookup

column and update the table name.


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Instead of using datasheet view, classic design view can also be used to modify the

table structure.

Design view in 2007 still maintains the classic view of design mode which allows user

to create the fields in rows. When adding fields to the table structure, few things has

to be considered and carefully set up. The first one is the data type. Choose suitable

data type for each field based on its usage. Table below shows the important data

types in Access and its description.

Data Type Description Example

Text Text character up to 255 character Names

Memo Up to 65300 alphanumeric characters

Address, notes

Number Numeric value Matrix number, Quantity

Date/Time Date and time Sales date

Currency Currency value Sales price

Auto Number Unique auto generated sequence numbers

Transaction number

Attachment Any binary file such as images and office file

Digital images

As stated earlier, this module will only discuss the creation of tables in Access; other

Access features will not be discussed. This is because query, form and report handling will

be done through Microsoft Visual Basic 2008.


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Chapter Exercises

Create the following tables in Sales database:

1. Table Name: Product

Field Name Data Type

ProductCode Text

ProductName Text

Brand Text

Model Text

Price Number

2. Table Name: Customer


CustID Text CustName Text

Address Text

Phone Text

Email Text

3. Table Name: SalesOrder


SONo Text

OrderDate Date/Time

CustID Text

ProductCode Text

Quantity Number


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Chapter Summary


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CHAPTER 2 :

STRUCTURED QUERY

LANGUAGE



Define the basic of SQL

Differentiate between

SQL and other

programming languages

Apply the basic command

of SQL data definition,

data manipulation and

data query language.


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2.0 STRUCTURED QUERY LANGUAGE

QL is an independent language that enables users to define database structures, manipulate its

content, perform data query and database administration. SQL is independent in nature because all

DBMS vendor use the same SQL standard. SQL is not a programming language, but it serves as a

specific language to manage data and perform data retrieval from any type of relational database.

Tracking down the history of SQL down the memory lane, we will found out that this powerful language was

developed at IBM laboratory by Donald Chamberlin and Raymond Boyce in 1972. In the early days, it is

called as SEQUEL and its functionality is limited to perform data retrieval only in the IBM relational database

environment.

Knowing its potential and future use, SEQUEL was later then standardized by ANSI (American National

Standard Institute) and the name was changed to SQL and pronounced as SEQUEL or ES QUE EL. Even

though SQL had been standardized by ANSI, there are many different versions of the SQL language

depending on the DBMS programs.

SQL is a standard language that only can be used to manage database and perform data retrieval only, not

more than that. SQL cannot be used to perform tasks that can be done by other programming languages

such as creating forms, button, handling exceptions and perform loop.

Because of these limitations, SQL has to be used with other third party programming languages or DBMS

tools such as C++, Java, ASP.Net, PHP, Visual Basic, Microsoft Access, MySQL, SQL Server and many

more.

SQL functionalities can be divided into three categories which are data definition, data manipulation and

data retrieval.

S

Relational

Database

Structure

End Users

End Users

DBMS (Database

Management System)

SQL


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2.1 SQL Data Types

Data types for SQL refer to the length and type of the field which is going to be created. SQL data

types are declared together with the database table structure. Below is the common data type that

is used in declaring table structure.

GROUP DATA TYPE USAGE

CHARACTER NUMBER (Long, Decimal) Numbers with specific length and decimal places

INTEGER Numbers without decimal places

NUMBER CHAR (Long) Fixed sized character up to 255 characters.

VARCHAR (Long) Varying size character

DATE DATE Dates in any format

TIME Time in any format

However, this data type is only common when standard SQL is used. Different vendors such as

Access and MySQL provide much more option such as CURRENCY, AUTONUMBER and many

more.

2.2 SQL as Data Definition Language

SQL can be used as a language to define a database. This includes the creation of database, the

creation of database objects such as tables, indexes and views and also performing administration

function on a database such as handling user access, table maintenance and setting up the

primary key for tables.

The basics of data definition language can be divided into three segments which are:

2.2.1 CREATE

Creates database components such as tables, indexes (search key), primary key and

views and also is used to create the database schema.

Examples:

CREATE TABLE Product

[field name] [data type] [constraint]

P_Code INTEGER NOT NULL UNIQUE,

P_Name VARCHAR (50) NOT NULL,

P_Price NUMBER (7,2) NOT NULL

This statement will create the following table structure


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2.2.2 ALTER

Modify existing database components structure such as add new field in table.

Examples:

ALTER TABLE Product

ADD P_Type CHAR(10) NOT NULL ,

ALTER TABLE Product

DROP COLUMN P_Type

2.2.3 DROP

Delete existing database components and is rarely used. This command is normally

used to delete users or table in database.

Examples:

DROP TABLE Product

In this book, data definition language will not be used together with Visual Basic 2008. This is

because most functions of DDL can be done effectively by using Access 2007 interface such as

table creation, altering and deleting tables.


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2.3 SQL as Data Manipulation Language

SQL data manipulation commands deals with the manipulation of data in database tables. Data

manipulation commands in SQL involve three important tasks which are:

2.3.1 Data Insertion

Data insertion command is used to insert new row (records) in a table by using the

INSERT INTO statements. INSERT INTO statements can be written in two options,

the first option is by specifically addressing the field names and the value that will be

inserted in the columns.

Examples:

[table] [table fields] [values]

INSERT INTO Product (P_Code, P_Name) VALUES (‘001’, ‘Pen’)

The second option of writing INSERT INTO statement doesn’t specify the specific

field to be inserted; only their values will be specified. This option is suitable when all

table fields are going to be given a value.

INSERT INTO Product VALUES (‘001’, ‘Pen’, ‘RM1’)

2.3.2 Data Update

Data update command is used to update existing records in table by using the

UPDATE SET statement.

Examples:

UPDATE Product SET P_Name = ‘Pencil’

UPDATE statement must be used together with the WHERE statement, otherwise, all

records in a table will be updated, in these case, all P_Name records in the table will

be changed to ‘Pencil’. The WHERE statement is a special syntax in SQL that is used

to filter records.

UPDATE Product SET P_Name = ‘Pencil’ WHERE P_Code = ‘001’

The above UPDATE statement will only changed the record where P_Code is equal

to ‘001’ only.


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2.3.3 Data Delete

Data deletion command is used to delete existing records in table by using the

DELETE statement.

Examples:

DELETE FROM Product

DELETE statement must be used together with the WHERE statement, otherwise, all

records in the table Product will be deleted and this operation cannot be undo.

DELETE FROM Product WHERE P_Code = ‘001’


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2.4 SQL as Data Query Language

Querying is considered as the most important and common function of SQL. The basic of querying

in SQL use SELECT statement to perform data retrieval from database tables. The results of

SELECT statement is stored in a temporary data reader such as record set (VB 2008) or result set

which also have the same structure in a form of rows and columns.

SQL SELECT statement can be used in a variety of ways and can be combined with multiple

functionalities. That’s why SELECT statement is considered as the most powerful statement in SQL

language.

2.4.1 Basic SELECT

Below is the ‘Product’ table

In order to select P_Code and P_Name from the table above, the SELECT statement

will look like :

SELECT P_Code, P_Name FROM Product

The results will be:

To retrieve all columns, use SELECT with *

SELECT * FROM Product

All columns will be selected.


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2.4.2 SELECT with WHERE

As mentioned before, WHERE statement is used to filter results or in SQL statement.

WHERE statement can be used together with UPDATE, DELETE and SELECT

statement as demonstrated in the UPDATE and DELETE examples.

SELECT statement below will retrieve data where the product type is equal to ‘Pencil’.

SELECT P_Code, P_Name FROM Product WHERE P_Type = ‘Pencil’

Below is the list of operations that can be used with WHERE

Operator Descriptions Examples

= Equal SELECT * FROM Product WHERE P_Type= ‘Pencil’

>,< Greater/smaller than SELECT P_Price FROM Product WHERE P_Price > RM 1

<> Not equal to SELECT * FROM Product WHERE P_Type <> ‘Pencil’

>=,<= Greater/smaller than or equal SELECT P_Price FROM Product WHERE P_Price > RM 1

LIKE Pattern search SELECT * FROM Product WHERE P_Type LIKE ‘Pen%’ *The result will display the list of records which the product type starts with Pen.... This means Pen and Pencil will be listed in the result set. *The % can also be used in front of the character for example %cil. In this case, the result will list product type which ends with the character ‘cil’.

BETWEEN Range search SELECT * FROM Product WHERE P_Price BETWEEN RM1 and RM1.50 *The result of the statement will display the result where product price in within the range of RM1 to RM 1.50 *BETWEEN can also be used to find range between characters, date and numbers.


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WHERE statement can also be used with AND and OR conditions.

SELECT P_Code, P_Name FROM Product WHERE P_Type = ‘Pencil’ OR P_Type =

‘Pen’

The statement above will display the product code and name where the type is either

‘Pen’ or ‘Pencil’.

SELECT P_Code, P_Name FROM Product WHERE P_Type = ‘Pencil’ AND P_Price

= RM 1.00

The statement above will display the record which the type is equal to Pencil and the

price is equal to RM 1.00.

2.4.3 SELECT with ORDER BY

Although simple in nature, ORDER BY is one of the most useful functions of SQL.

ORDER BY can be used to sort records in ascending or descending mode. ORDER

BY statement located at the end of SELECT statement.

SELECT * FROM Product ORDER BY P_Code Asc

ASC stands for ascending order by DESC stands for descending order.


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2.4.4 SELECT with FUNCTIONS

SQL has many useful functions that can be used either to perform calculations, string

operations or formatting. Below is the list of some useful SQL functions that can be

used together with SELECT statement.

Functions Descriptions Examples

AVG Calculate average SELECT AVG (P_Price) AS AvgPrice FROM Product

SUM Accumulate sum SELECT SUM (P_Price) AS SumPrice FROM Product

COUNT Count number of records SELECT COUNT (*) AS RecCount FROM Product

MAX Find maximum value SELECT MAX (P_Price) AS MaxPrice FROM Product

MIN Find minimum value SELECT MIN (P_Price) AS MinPrice FROM Product

FIRST Search for first value SELECT FIRST (P_Code) AS FirstCode FROM Product

LAST Search for last value SELECT LAST (P_Code) AS LastCode FROM Product

2.4.5 SELECT with GROUP BY

The GROUP BY statement is very useful in grouping the result set in one or more

columns. GROUP BY statement is normally used with aggregate functions.

P_Id PurchaseDate PurchasePrice Customer

1 2008/11/12 1000 Hisham

2 2008/10/23 1600 Hadzrami

3 2008/09/02 700 Hisham

4 2008/09/03 300 Hisham

5 2008/08/30 2000 Raudah

6 2008/10/04 100 Hadzrami

GROUP BY statement can be used in the above situation to group the result for example to find the total purchase of each customer.

SELECT Customer,SUM(PurchasePrice) FROM Purchases GROUP BY Customer

The result-set after the SQL statement had been executed will look like this:

Customer SUM(PurchasePrice)

Hisham 2000

Hadzrami 1700

Raudah 2000


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Chapter Exercise :

The contents of Product table are as follows:

Product

Code Name Model Siz

e QtyOnHand

Reorder

Qty

Pric

e Vendor

2407WF

P

Ell 24" 2407WFP TFT LCD Monitor Ell 24 6 2 249

9

ABC S/B

AL2216

W

Acer 22" AL2216W LCD Monitor Acer 22 3 2 129

9

M Ent

BFP73

G

BenQ 17" FP73G+ TFT LCD Monitor BenQ 17 2 2 599 M Ent

BFP92

W

BenQ 19" FP92W TFT LCD Monitor BenQ 19 5 2 639 M Ent

E156FP Ell 15" E156FP TFT LCD Monitor Ell 15 1 2 499 ABC S/B

E177FP Ell 17" E177FP TFT LCD Monitor Ell 17 5 2 569 ABC S/B

L1752S LG 17" L1752S TFT LCD Monitor LG 17 1 2 575 HMP S/B



S732N Samsung Syncmaster 732N - 17"

Monitor

Samsung 17 5 2 599 XYZ Ent.

S740N Samsung Syncmaster 740N - 17"

Monitor


S932B Samsung Syncmaster 932B - 19"

Monitor


S940B

W

Samsung Syncmaster 940BW - 19"

Monitor


VA912B Viewsonic VA912B 19" TFT Monitor Viewsonic 19 1 2 799 ABC S/B


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REQUIRED:

(a) Write the SQL code to display the 17” (inches) monitors that have reached or exceeded the

reorder quantity as shown in Query1 table below.

Query1

Name Model Price

BenQ 17" FP73G+ TFT LCD

Monitor

BenQ 599

LG 17" L1752S TFT LCD

Monitor

LG 575

(b) Write the SQL code to display the monitors which price is above RM1000 as shown in Query2

table below.

Query2

Name Model Price

Acer 22" AL2216W LCD Monitor Acer 1299

Ell 24" 2407WFP TFT LCD Monitor Ell 2499

(c) Write the SQL code to change the reorder quantity from 2 units to 3 units for all models.

(d) Write the SQL code to delete a record for monitor with the product code L1952S.

(e) Write the SQL code to insert the following data.

Code Name Model Siz

e QtyOnHand

Reorder

Qty

Pric

e Vendor

1999E Dell Studio Laptop Dell 14 7 3 249

9

MHS/AM


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Chapter Summary


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CHAPTER 3:

DATABASE

PROGRAMMING USING

OLEDB TECHNIQUE


chapter, you should be able to:

Establish database

connection between

Visual Basic and Access

Perform database

manipulation and query

using VB and SQL

statement.

Use components such as

Data Grid and List View

to perform database

manipulation.


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3.0 DATABASE PROGRAMMING USING OLEDB TECHNIQUE

3.1 Database Connectivity

In this part, we will learn about the objects that we can use to open and read data from a database. We

will be using MS Access 2007 as our database.

The Connection Object

We need to establish connection to a database before your application can manipulate the database

such data insertion, deleting, updating or searching. So we need a Connection Object to enable us to

connect to a database.

There are a number of different connection objects, and it depends largely on the type of database

you're connecting to. For our application, we will be using MS Access 2007 database, so we will need

something called the OLE DB connection object.

OLE stands for Object Linking and Embedding that allow you to connect to data sources in general, and

not just databases. You can use it, for example, to connect to text files, SQL Server, email, etc.

There are a number of different OLE DB objects (called data providers), because we are using Access

2007, so we will use "Microsoft.ACE.OLEDB.12.0". (Note: If you’re using MS Access 2003 version you

have to use Microsoft.Jet.OLEDB.4.0 data provider).


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Establishing Database Connection

Let us begin our lesson on how to create connection to a database.

Create a new project and renamed it as OleDBExample.

Click File Save All, to save your project.

Browse the location you want to store your project.

Explanation: In this example, the project is saved inside My Documents folder. You can change the

location/directory where you want to save your project.)


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Open your Windows Explorer and look for OleDBExample folder.

Double click the folder and you will see your folder as follows.

Now, we’re going to create/add Data folder inside bin folder.

Double click the bin folder, add a new folder and rename it as Data.

The next step is to copy your database file that you have created in the previous section into the Data

folder.

Find the Sales.accdb file in My Documents folder, right-click, cut the file and paste it inside the Data

folder.

You should be able to see Sales.accdb inside the Data folder.


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Interface Design

Back to our Project, place a button on your form and set the Name and Text properties to LoadButton

and Load accordingly.

Double click your button to open up the code window. Add the following codes:

Const cnString As String = "PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source = ..\Data\Sales.accdb"

Dim con As OleDb.OleDbConnection

con = New OleDbConnection(cnString)

con.Open()

MsgBox("A Connection to the Database is now open")

con.Close()

MsgBox("The Connection to the Database is now Closed")

Note: If you are using Access 2003, replace the first line with the following code:

Const cnString As String = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = ..\Data\Sales.accdb"


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At the very top of your code window, before Public Class Form 1, type the following:

Imports System.Data.OleDb

Your coding window should now look like this:

Test out your code by running your program.

Click Load button and the following message boxes should display to show the connection to the database is

open. Click OK and you will see the second message box.

Troubleshooting: If the message box does not appear, make sure your Data Source path is correct. The

database file (Sales.accdb) should be located inside Data folder, Data folder should be located inside bin folder

and bin folder should be located inside OleDBExample folder as follows.


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Explanation:

If we look at the code below, we will notice that there are two things stated in the Connection Object: the

technology to do the connecting to our database; and the location of the database. The technology is called the

Provider; and you use "Data Source" to specify where your database is.

Notice the two parts, separated by a semi-colon:

1st Part: PROVIDER= Microsoft.ACE.OLEDB.12.0 2nd Part: Data Source = ..\Data\Sales.accdb

The first part specifies which provider technology we want to use to do the connecting which is ACE (For Access 2003, the provider technology is Jet). The second part, typed after a semi-colon, points to where the database is. In the above code, the database is in the Data folder which is inside bin folder and inside OleDBExample (your project) folder. The name of the Access file we want to connect to is called Sales.accdb.


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3.2 Database Manipulation & Query

In previous section, you have learned on how to establish connection to database. In the next section, we will

look into how to Insert, Update and Delete record.

Adding Project Module

We have seen that whenever the application wants to interact with the database, we need to establish the

database connection. Therefore, every form that we want to add into the project, which interact with the

database, must include the following code.

Const cnString As String = "PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source = ..\Data\Sales.accdb"

Dim con As OleDb.OleDbConnection

con = New OleDbConnection(cnString)

In order to simplify the code, the best practice is, we add a module into our project and write the code which we

will be using repeatedly in the module.

Click Project Add Module

Rename the module name as ProjectModule and click Add.

Inside the module, add in the following line (Note: The statement should be in a single line and not three as it is

below):


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Public Const conString As String = "PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source =

..\Data\Sales.accdb"

Public conn As OleDbConnection = New OleDbConnection(conString)

At the very top of your code window, before Module ProjectModule, type the following:


Your coding window should now look like this:

Insert New Record.

Previously, you have created database named Sales.accdb with three tables, Product, Customer and

SalesOrder. So now, we are going to create a form that will serve as an interface for user to add new record into

the Product table.

Add new windows form and rename it as InsertProductForm.

Add five TextBox on the form as the number of fields in Product table is five. Set the Name properties as follows:

1. ProductCodeTextBox 2. ProductNameTextBox 3. BrandTextBox 4. ModelTextBox 5. PriceTextBox

Add three buttons; Save (Text: Save, Name: SaveButton), Clear (Text: Clear, Name: ClearButton) and Exit (Text:

Exit, Name: ExitButton).


[35]

Your form should looks as the following figure.

Double click Save button and write the following codes.

Dim sqlQRY As String = "INSERT INTO Product Values ('" & ProductCodeTextBox.Text & "', '" &

ProductNameTextBox.Text & "', '" & BrandTextBox.Text & "', '" & ModelTextBox.Text & "', '" & PriceTextBox.Text

& "' )"

Try

conn.Open()

Dim cmd As OleDbCommand = New OleDbCommand(sqlQRY, conn)

cmd.ExecuteNonQuery()

MsgBox("Record Inserted")

Catch ex As OleDbException

MsgBox("Error: " & ex.ToString & vbCrLf)

Finally

conn.Close()

End Try


[36]

At the very top of your code window, before Public Class InsertProductForm, type the following:


Double click Clear button and write the following codes.

ProductCodeTextBox.Clear()

ProductNameTextBox.Clear()

BrandTextBox.Clear()

ModelTextBox.Clear()

PriceTextBox.Clear()

ProductCodeTextBox.Focus()

Double click Exit button and write the following code.

Me.Close()

Your coding window should now look like this (Only part of the Sql statement can be seen, the whole Sql

statement (above) should be entered in a single line):


[37]

Finding/Searching Record

Another important component in database is a search function. In this example, we’re going to create a new form

to search record in the Product table based on the Product Code entered by the user.

Create a new windows form and name it as SearchForm. Design your form and set the properties as follows:


Create a Search button and name it as SearchButton.

Double-click it and enter the following codes:

Dim ResultString As String

Dim sqlQRY As String = "SELECT * FROM Product WHERE ProductCode = '" & ProductCodeTextBox.Text & "'"

Dim conn As OleDbConnection = New OleDbConnection(conString)

Try

conn.Open()



[38]

Dim rdr As OleDbDataReader = cmd.ExecuteReader

While (rdr.Read)

ResultString = rdr("ProductCode").ToString()

NameTextBox.Text = rdr("ProductName").ToString()

BrandTextBox.Text = rdr("Brand").ToString()

ModelTextBox.Text = rdr("Model").ToString()

PriceTextBox.Text = rdr("Price").ToString()

End While

If ResultString <> ProductCodeTextBox.Text Then

MsgBox("Record Not Found")

CodeTextBox.Clear()

CodeTextBox.Focus()

End If



Finally

conn.Close()

End Try


[39]

At the very top of your code window, before Public Class SearchForm, type the following:


Your coding window should now look like this (The Sql statement should be entered in a single line):

Now, we are going to add in another two buttons that are Update and Delete buttons. Create an Update and

Delete buttons and name them as UpdateButton and DeleteButton accordingly.


[40]

Double-click the UpdateButton and enter the following codes:

Dim sqlQRY As String = "UPDATE Product SET ProductName='" & NameTextBox.Text & "', Brand='" &

BrandTextBox.Text & "', Model='" & ModelTextBox.Text & "', Price='" & PriceTextBox.Text & "' WHERE

ProductCode='" & ProductCodeTextBox.Text & "'"

Try

conn.Open()



MsgBox("Record successfully saved...", MsgBoxStyle.Information)



Finally

conn.Close()

End Try

Your coding window should now look like this (The Sql statement should be entered in a single line):


[41]

Double-click the DeleteButton and enter the following codes:

If MessageBox.Show("Do you really want to Delete this Record?", _

"Delete", MessageBoxButtons.YesNo, _

MessageBoxIcon.Warning) = DialogResult.No Then

MsgBox("Operation Cancelled")

Exit Sub

End If

Dim sqlQRY As String = "DELETE FROM Product WHERE ProductCode='" & ProductCodeTextBox.Text & "'"

Try

conn.Open()



MsgBox("Record successfully deleted...", MsgBoxStyle.Information)

ProductCodeTextBox.Clear()

NameTextBox.Clear()

BrandTextBox.Clear()

ModelTextBox.Clear()

PriceTextBox.Clear()



Finally

conn.Close()

End Try


[42]

Your coding window should now look like:

Data Grid

We can use data grid object to perform database manipulation function such as Insert, Delete and Update.

Add a new form and name it as ProductDataGridForm.

Look for DataGridView object inside Data Toolbox and create the DataGridView onto the form.

Set the DataGridView Name properties as Product DataGridView.

Add a button onto the form, set it’s Name as SaveButton and it’s Text as Save.


[43]

At the very top of your code window, before Public Class ProductDataGridViewForm, type the following:


Add the following codes after Public Class ProductDataGridViewForm

Dim da As OleDbDataAdapter

Dim ds As DataSet = New DataSet

Dim sqlQRY As String

Double click Save button and write the following codes:

da.Update(ds, "Product")

Now we need to add codes for form load event.

Double-click the form (be careful not to click the DataGridView object) and add the following codes:

sqlQRY = "SELECT * FROM Product"

Try

conn.Open()

da = New OleDbDataAdapter(sqlQRY, conn)

Dim cb As OleDbCommandBuilder = New OleDbCommandBuilder(da)


[44]

da.Fill(ds, "Product")

ProductDataGridView.DataSource = ds

ProductDataGridView.DataMember = "Product"


MsgBox(ex.ToString)

Finally

conn.Close()

End Try



[45]

Test the code, by running the application. You will see the form as follow:

In this DataGridView form you will see two records that have been added earlier. You can do all the database

operation such as inserting new record, updating record deleting as if you are using MS Access table.

All database manipulation operation above will NOT have any effect on the records in the database, unless you

need click Save button.


[46]

List View

We will introduce to you another object that can retrieve and display all records from a database table, the

ListView object.

Before we add a new form into our project, we need to add the following code into our ProjectModule.

Public Enum FormState

adStateAddMode = 0

adStateEditMode = 1

End Enum

Public Sub FillListView(ByRef lvList As ListView, ByRef myData As OleDbDataReader)

Dim itmListItem As ListViewItem

Dim strValue As String

Do While myData.Read

itmListItem = New ListViewItem()

strValue = IIf(myData.IsDBNull(0), "", myData.GetValue(0))

itmListItem.Text = strValue

For shtCntr = 1 To myData.FieldCount() - 1

If myData.IsDBNull(shtCntr) Then

itmListItem.SubItems.Add("")

Else

itmListItem.SubItems.Add(myData.GetValue(shtCntr))

End If

Next shtCntr

lvList.Items.Add(itmListItem)

Loop

End Sub


[47]

Public Function ExecNonQuery(ByVal strSQL As String)

Dim conTable As OleDbConnection

conTable = New OleDbConnection

Try

With conTable

If .State = ConnectionState.Open Then .Close()

.ConnectionString = conString

.Open()

End With

Dim cmd As OleDbCommand = New OleDbCommand(strSQL, conTable)


Return True


Return ex

Finally

conTable.Close()

End Try

End Function


[48]

Public Function GetData(ByVal sSQL As String)

Dim cnTable As OleDbConnection

Dim sqlCmd As OleDbCommand = New OleDbCommand(sSQL)

Dim myData As OleDbDataReader

cnTable = New OleDbConnection(conString)

Try

cnTable.Open()

sqlCmd.Connection = cnTable

myData = sqlCmd.ExecuteReader

Return myData

Catch ex As Exception

Return ex

End Try

End Function



[49]

Now, we will move to the next part, which is adding a new form and a ListView object.

Add a new windows form and rename it as ProductListForm.

Add the ListView object onto the form and rename it as ProductListView.

Add two buttons, Add and Delete and name them as AddButton and DeleteButton.


[50]

Double-click on the form (not the ListView object) to add the following codes:

sSql = "SELECT * FROM Product ORDER BY ProductCode ASC"

Call FillList()

At the very top of your code window, before Public Class ProductListForm, type the following:


Declare the following variable after Public Class ProductListForm:

Dim sSql As String



[51]

Now add the FillList sub procedure as follows:

Private Sub FillList()

With ProductListView

.Clear()

.View = View.Details

.FullRowSelect = True

.GridLines = True

.Columns.Add("Product Code", 100)

.Columns.Add("Product Name", 150)

.Columns.Add("Brand", 140)

.Columns.Add("Model", 130)

.Columns.Add("Price", 130)

FillListView(ProductListView, GetData(sSql))

End With

End Sub

Run your project and you get the following output (Note: The records in the ListView are the records you have

previously entered into your product table).


[52]

Next, we are going to add instructions for Delete button.

Double-click the Delete button and add the following codes:

Dim ProdCode As String

If MessageBox.Show("Do you really want to Delete this Record?", _

"Delete", MessageBoxButtons.YesNo, _

MessageBoxIcon.Warning) = DialogResult.No Then

MsgBox("Operation Cancelled")

Exit Sub

End If

For Each sItem As ListViewItem In ProductListView.SelectedItems

ProdCode = sItem.Text

Next

If ProdCode <> "" Then

Dim strDeleted As Boolean

strDeleted = ExecNonQuery("DELETE Product.ProductCode FROM Product WHERE ProductCode= '" &

ProdCode & "'")

If strDeleted = "True" Then

MsgBox("Record's deleted.", MsgBoxStyle.Information)

Call FillList()

Else

MsgBox(strDeleted)

End If

Else

MsgBox("Please select record to delete.", MsgBoxStyle.Critical)

End If



[53]

Run your project. First you need to select the record by clicking the record (click once, don’t double-click).

Click the Delete button and you will be prompted with the warning message.

Click Yes to proceed or No to cancel the operation.

Now, we will proceed with the Add button where we need to create a new form.

Create the following form and name it as ProductAddFromLV.


[54]

Set the following name properties for textboxes:


Set the following name properties for buttons:

1. SaveButton 2. CloseButton

Double-click the Close button and type the following code:

Me.Close()

Double-click the Save button and type the following code:

Dim dt As DataTable = dsProduct.Tables("Product")

If ProductCodeTextBox.Text = "" Or ProductNameTextBox.Text = "" Then

MsgBox("Please fill up Product Code No or Name information.", MsgBoxStyle.Critical)

Exit Sub

End If

Try

If State = ProjectModule.FormState.adStateAddMode Then

Dim newRow As DataRow

newRow = dt.NewRow()

newRow("ProductCode") = ProductCodeTextBox.Text

newRow("ProductName") = ProductNameTextBox.Text

newRow("Brand") = IIf(BrandTextBox.Text = "", System.DBNull.Value, BrandTextBox.Text)

newRow("Model") = IIf(ModelTextBox.Text = "", System.DBNull.Value, ModelTextBox.Text)

newRow("Price") = IIf(PriceTextbox.Text = "", System.DBNull.Value, PriceTextbox.Text)

dt.Rows.Add(newRow)

Else

With dt


[55]

.Rows(0)("ProductCode") = ProductCodeTextBox.Text

.Rows(0)("ProductName") = ProductNameTextBox.Text

.Rows(0)("Brand") = IIf(BrandTextBox.Text = "", System.DBNull.Value, BrandTextBox.Text)

.Rows(0)("Model") = IIf(ModelTextBox.Text = "", System.DBNull.Value, ModelTextBox.Text)

.Rows(0)("Price") = IIf(PriceTextbox.Text = "", System.DBNull.Value, PriceTextbox.Text)

End With

End If

daProduct.Update(dsProduct, "Product")

MsgBox("Record successfully saved.", MsgBoxStyle.Information)


MsgBox(ex.ToString)

End Try


Now, go back to ProductListForm and double-click Add button

Dim ProductAddFromLV As New ProductAddFromLV


[56]

ProductAddFromLV.State = ProjectModule.FormState.adStateAddMode

ProductAddFromLV.ShowDialog()

Call FillList()

Your coding window for Add button should now look like:

Now run the ProductListForm and click Add button.

Enter test data and click Save. You will be prompted with the message box saying record successfully saved.


[57]

Chapter Exercise


[58]

CHAPTER 4:

DATABASE

PROGRAMMING

USING ADODB

TECHNIQUE


chapter, you should be able to:

Establish database

connection between

Visual Basic and Access

using ADODB method

Perform database

manipulation and query

using VB and SQL

statement through

ADODB method and

components.


[59]

4.0 DATABASE PROGRAMMING USING ADODB (ActiveX Data Objects)

In the previous chapter, the concept of OLEDB was introduced. Examples on how to perform database

connection and manipulation is also explained by using the OLEDB technique. In this chapter, the concept

of ADODB will be used to demonstrate database connectivity and manipulation through examples.

Microsoft ActiveX Data Objects or widely known as ADODB is the latest version of earlier components such

as RDO (Remote Data Objects) and DAO(Data Access Objects) to perform data access to relational

database. ADODB can be said as a middleware between programming languages to database.

ADODB has three basic functionalities which are:

i. Establishing connection between programming languages and database. In this book, Visual Basic

is the programming languages and Access 2007 is used as the database.

ii. Data retrieval through the use of recordset. Recordset is used to store temporary data retrieved

from database through SQL query statement (SELECT).

iii. Perform changes to the database through SQL manipulation statement (INSERT, UPDATE,

DELETE).

In this chapter, step by step example on how to develop a simple database application will be explained. A

simple student registration system will be used as the example. This program will have one login form and

one main form that will act as the simple registration form.

4.1 Step 1 : Creating the database

The initial step in this project is to create the database and its object that is going to be used in the

programming project. Create a database and name it as dbADOExample

In the database, create the following tables.

Table Name : tblLogin

Field Name Data Type Size

UserName Text 255

UserPassword Text 255

UserLevel Text 255


[60]

Table Name: tblRegistration


StudMatric Text 255

StudName Text 255

StudCourse Text 255

StudCollege Text 255

StudPhone Text 255

StudSem Number 255

Table Name: tblCourse


CourseCode Text 255

CourseName Text 255

After all the tables had been created, fill in each table with these values:

tblLogin is related with tblRegistration in a 1:1 relationship. This is because one student can only

have one user name and one user name can be owned by only one user.

tblCourse is related with tblRegistration in a 1:M relationship. This is because one student can only

take one course and one course can be taken by many students.


[61]

4.2 Step 2 : Designing application interface

The second step is to create the application interface by using Visual Basic form. In this application,

four forms will be created which are:

i. frmLogin

frmLogin will be used to authenticate each user that is going to enter the system. If the

user is new to the system, they have to contact the system administrator to register their

user name and password. System administrator will register their names and level in the

administration form.

There will be two level of access; level 1 is the system administrator which is the super

user and level 2 is for normal user to view and modify their own data only.

User will have to enter their user name and password, if the password entered doesn’t

match the user name or the other way round, user will not be allowed to enter and a

warning message box will be displayed.

Set the properties of the objects as follows:

Object Property

User name and password text box

Name: txtUserName txtPassword

Password text box Password Char = *

Login and logout button Name: cmdLogin cmdLogout


[62]

ii. frmRegister

frmRegister will be used as the main form to register the details of the student. This form

contains toolbar to navigate between forms, a list to display existing data, a button to

perform search based on matric number and command buttons to execute SQL

statements.

More details on how this form is going to work will be explained more on later stages of

this chapter.

1

2

3

4

5


[63]

Set the properties of the object as follows:

Reference Object Property

1 Toolstrip Name: ToolStrip1 Items: Label1 Text : Admin Image Scaling : None TextImage Relation : ImageAboveText Label2 Text : Admin Image Scaling : None TextImage Relation : ImageAboveText Label3 Text : Admin Image Scaling : None TextImage Relation : ImageAboveText Images : any suitable icons for each of the items

2 Listview (must be associated with an image list)

Name: lstStudentList imageList1 (associated components) View: Details Small ImageList Imagelist1

3 Matric no, Name, Phone and Semester text box

Name: txtMatric txtName txtPhone txtSemester

4 Course and college combo box

Name: cmbCourse cmbCollege

5 Search, Insert, Update, Delete and Clear command button

Name: cmdInsert cmdUpdate cmdDelete cmdClear


[64]

iii. frmCourse

frmCourse will be used as the interface to the administrator to perform course

maintenance (add, delete or update course).

This form will consist of list displaying all course available and buttons to execute the SQL

statement.


Object Property

Search, Course code and Course name text box

Name: txtSearch txtCourseCode txtCourseName

Insert, Update, Delete, Clear and Exit command button

Name: cmdInsert, cmdUpdate, cmdDelete, cmdClear cmdExit

Course listview Name: lstCourseList imageList1 (associated components) View: Details Small ImageList Imagelist1


[65]

iv. frmAdmin

frmAdmin will be used as the interface to the administrator to perform user maintenance

(add, delete or update user).

This form will consist of list displaying all users available and buttons to execute the SQL

statement.


Object Property

Search, user name and user password name text box

Name: txtSearch txtUserName txtPassword

Insert, Update, Delete, Clear and Exit command button

Name: cmdInsert, cmdUpdate, cmdDelete, cmdClear cmdExit

Course listview Name: lstUserList imageList1 (associated components) View: Details Small ImageList Imagelist1


[66]

4.3 Step 3 : Adding project components

The third step involves establishing connections and database variables that is going to be used in

the project. All the connection properties and public variables will be stored in a module.

In order to create a module, click at the add new item icon and click at add module.

The default name for the module is Module1.vb, rename the module as dbConnection.vb to make it

more meaningful.

In order to use ADODB components, it has to be initialized, to do this, go to Project -> Add

Reference and click at adodb then click ok. This step is very important because adodb components

will not be feasible throughout the project if it’s not been initialized.


[67]

4.4 Step 4 : Variable declaration

By adding adodb components, we can use its object in this project, but before it can be used, it has

to be declared. Below are the list of adodb objects that is going to be used in the project and its

declaration. Note that all the declaration had to be done in the dbConnection module.

Object Description Declaration

Recordset Used to hold a set of records from database table in rows and columns format.

Public rec1 as ADODB.recordset

Connection Create a connection to database. Public con as ADODB.connection

Besides ADODB variables, there are also other variables that will be used throughout the project.

Below are the common variables that are used in a database programming project.

Description Data Type Declaration

Used to hold the connection string String Public strConnection as String

Used to hold SQL statement String Public strSQL as String

Used to hold user name, password and level field

String Public strUserName, strPassword, strLevel as String

All variable declaration should be done on the declaration section.


[68]

4.5 Step 5 : Connection String & Data Source

In order to create a connection with the database (in this case the database is dbADOExample),

the connection string and the data source has to be establish in the module.

Code Description Public Sub conn() Sub procedure header Con = New ADODB.Connection Initializing connection object Con.ConnectionString = "PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source = C:\Users\hishamuum\Documents\dbAdoExample.accdb"

Setting up the connection string provider. For Access 2007, the provider is Microsoft.Ace.OLEDB.12.0 Data source is the path where the database is being kept.

Con.Open() Opening the connection rec1 = New ADODB.Recordset Initializing recordset object End Sub Closing procedure header

Public rec1 As ADODB.Recordset

Public Con As ADODB.Connection

Public strConnection As String

Public strUserName As String

Public strPassword As String

Public strLevel As String

Public strSql As String

Public Sub conn()

Con = New ADODB.Connection

Con.ConnectionString =

"PROVIDER=Microsoft.ACE.OLEDB.12.0;Data Source =

C:\Users\hishamuum\Documents\dbAdoExample.accdb"

Con.Open()

rec1 = New ADODB.Recordset

End Sub

4.6 Step 6 : Connection State

When performing query, the connection state of recordset is important, each time a query is

executed, the recordset must be not be in active state. To ensure this, a procedure has to be

created and this procedure must be called each time a query is executed to ensure that the correct

state of the recordset is in place. The code is as below and also located in dbConnection module.

Public Sub checkConn()

If rec1.State = 1 Then rec1.Close()

End Sub


[69]

4.7 Step 7 : Form Code

4.7.1 frmLogin

There are two important events that has to be coded in the frmLogin. The first one is

form load event and the second would be the buttons click event.

Form Load:

Double click anywhere (except on the objects such as text box) on the form and form

load event header will be generated. In this event, call the procedure conn from the

dbConnection module by writing its name to establish the connection with the

database (dbADOExample.accdb).

Public Class frmLogin

Private Sub frmLogin_Load(ByVal sender As

System.Object, ByVal e As System.EventArgs) Handles

MyBase.Load

conn()

End Sub

End Class

Login button:

Double click on top of the login button and the click event header for login button will

be generated.

Private Sub cmdLogin_Click(ByVal sender As System.Object,

ByVal e As System.EventArgs) Handles cmdLogin.Click

End Sub

Validating the input

If txtUserName.Text = "" Or txtPassword.Text = "" Then

MsgBox("Incomplete Login Information, Please Try

Again")

Exit Sub

End If

The block of code above is to ensure system user cannot enter the system if the user

name or password text box is empty.


[70]

Retrieve user information to perform authentication

checkConn()

strSql = "SELECT * FROM tblLogin WHERE UserName='" &

txtUserName.Text & "'"

rec1.Open(strSql, Con, ADODB.CursorTypeEnum.adOpenStatic)

User information will be retrieved from the database where the user name entered in

the text box is similar with the user name from the table.

Code Description checkConn() Close the recordset strSql = "SELECT * FROM tblLogin

WHERE UserName='" &

txtUserName.Text & "'"

SQL statement to retrieve data from tblLogin

rec1.Open(strSql, Con,

ADODB.CursorTypeEnum.adOpenStatic) Execute the SQL statement

If rec1.Fields("UserName").Value = txtUserName.Text And

rec1.Fields("UserPassword").Value = txtPassword.Text Then

strUserName = rec1.Fields("UserName").Value

strPassword = rec1.Fields("UserPassword").Value

strLevel = rec1.Fields("UserLevel").Value

frmRegister.Show()

Me.Hide()

Else

MsgBox("Wrong Login Information, Please Try Again")

txtUserName.Text = ""

txtPassword.Text = ""

Exit Sub

End If

If the user name and password entered in the login menu match with the data from

the database, frmRegister will be displayed and the login information retrieved from

the database will be assigned to the global variables (strUserName, strPassword and

strLevel) to be used throughout the program

Code Description If rec1.Fields("UserName").Value =

txtUserName.Text And

rec1.Fields("UserPassword").Value

= txtPassword.Text Then

Matching the username and password entered by the user with the data extracted from tblLogin

strUserName

=rec1.Fields("UserName").Value

strPassword

=rec1.Fields("UserPassword").Value

strLevel

= rec1.Fields("UserLevel").Value

Assigning values from tblLogin to the global variable

frmRegister.Show()

Me.Hide() Hide the login form and displaying the frmRegister

MsgBox

("Wrong Login Information,

Please Try Again")

txtUserName.Text = ""

txtPassword.Text = ""

Displaying warning if login information wrongly entered


[71]

4.7.2 frmRegister

frmRegister is the most important form in this project. It contains the list of students

and has the functionalities to maintain the student information. The function of

frmRegister can be divided into two main categories, the first one is to display the

data on the objects and the second one would be maintaining the data (insert, update,

delete).

On top of the form is the toolbar which is used to navigate between forms in this

application. The code for the toolbar is as below (double click on each item on the

toolbar):

Private Sub ToolStripLabel1_Click(ByVal sender As


ToolStripLabel1.Click

frmAdmin.Show()

End Sub




frmCourse.Show()

End Sub




End

End Sub


[72]

Displaying data retrieved from tables involves the use of two objects in this form. The

objects are listview and combo box.

Displaying data from tables in listview.

The listview on the left side of the form will be programmed two have two main

functionalities which are displaying the data from tblRegister and for user to select

records from the list. This is done by double clicking on specific record in the list.

Declare the variables that are going to be used. Declarations are being made at the

declaration section on top of the code window.

Private X As Integer

Private lst As ListViewItem

Private lvwColumn As ColumnHeader

Private shtCntr As Short

The variable X and shtCntr will be used as counters while lst and lvwColumn will be

used to store data list item and column header item.

Create a sub procedure to specifically handle the data retrieval and data loading

function into the list.

Private Sub loadList()

End Sub

Write all the code below in the above sub procedure.

Retrieve the data from tblRegister by using the following statements.

checkConn()

strSql = "SELECT StudMatric,StudName FROM tblRegister"


To generate the listview header based on fields from tblRegister, use the following

code.

ListView1.Clear()

For Me.shtCntr = 0 To 1

lvwColumn = New ColumnHeader()

lvwColumn.Text = rec1.Fields(shtCntr).Name

ListView1.Columns.Add(lvwColumn)

Next


[73]

Code Description ListView1.Clear() Clear the list view from past data For Me.shtCntr = 0 To 1 Determining the number of field to be

generated as column header. The index counter depends on the number of header to be displayed.

lvwColumn = New ColumnHeader()

lvwColumn.Text =

rec1.Fields(shtCntr).Name

ListView1.Columns.Add(lvwColumn)

Adding the field as the column header.

Next

After generating the header, next step is to fill the list with data retrieved from

tblRegistration using SQL statement. Use the following codes.

While Not rec1.EOF

lst = New ListViewItem

lst.Text = rec1.Fields(0).Value

For Me.X = 1 To 1

lst.SubItems.Add(rec1.Fields(X).Value)

Next X

rec1.MoveNext()

ListView1.Items.Add(lst)

End While

Code Description While Not rec1.EOF Navigate throughout the

recordset until end of record. lst = New ListViewItem

lst.Text = rec1.Fields(0).Value Initialize the listview and set the first item in the listview item

For Me.X = 1 To 1

lst.SubItems.Add(rec1.Fields(X).Value)

Next X

Adding subitems to the listview item.

End While End the loop when end of record reached in the recordset.

The final step to load the data into the list is to call the procedure from form load

event.

Private Sub frmRegister_Load(ByVal sender As


MyBase.Load

loadList()

End Sub


[74]

The loaded list will display data from tblRegistration.

Selecting Data from List

The next step is to write the code to select data from the list. Through this function,

user will be able to select any item from the list by double clicking on specific record.

Selecting data from the list will be done using the double click event of the list view.


[75]

The default event for the listview when it is being double clicked is

SelectedIndexChanged, to change this value, change the event to Double click.

Private Sub ListView1_DoubleClick(ByVal sender As Object,

ByVal e As System.EventArgs) Handles

ListView1.DoubleClick

End Sub

Fill in the sub procedure with the code below to retrieve the data selected and display

it in the text and combo boxes.

'retrieve the specific data selected from the list

checkConn()

strSql = "SELECT * FROM tblRegistration WHERE

StudMatric='" & ListView1.SelectedItems(0).Text & "'"


'assign each text boxes with specific fields

txtMatricNo.Text = rec1.Fields("StudMatric").Value

'assign studmatric variables with selected value(to be

used when performing update and delete

strStudMatric = txtMatricNo.Text

txtName.Text = rec1.Fields("StudName").Value

cmbCourse.Text = rec1.Fields("CourseCode").Value

cmbCollege.Text = rec1.Fields("StudCollege").Value

txtPhone.Text = rec1.Fields("StudPhone").Value

txtSemester.Text = rec1.Fields("StudSem").Value


[76]

Performing Data Manipulation

Performing data manipulation in this application involves the use of three important

SQL commands for data manipulation which are; INSERT, UPDATE and DELETE.

The data manipulation function will be done through the click event of command

button.

UPDATE & DELETE existing data

After selecting which data to be edited, the next process is to write the SQL statement

to execute the UPDATE operation. Double click cmdUpdate and cmdDelete Button

and write the following code:

Private Sub cmdUpdate_Click(ByVal sender As


cmdUpdate.Click

strSql = "UPDATE tblRegistration SET StudName='"

& txtName.Text & "',StudPhone='" & txtPhone.Text

& "',StudSem='" & txtSemester.Text & "' WHERE

StudMatric='" & strStudMatric & "'"

Con.Execute(strSql)

loadList()

End Sub

Field involves in the update process are StudName, StudPhone and StudSem. strStudMatric variable which is retrieved when the list is selected is used as the condition. loadList() procedure is called to refresh the list each time UPDATE and DELETE statement is being executed.

Field involves in the update process are StudName, StudPhone and StudSem. strStudMatric variable which is retrieved when the list is selected is used as the condition in the UPDATE and DELETE statement. All text boxes is being cleared after the deletion process.

Private Sub cmdDelete_Click(ByVal sender As


cmdDelete.Click

strSql = "DELETE FROM tblRegistration WHERE

StudMatric='" & strStudMatric & "'"

Con.Execute(strSql)

txtMatricNo.Text = ""

strStudMatric = ""

txtName.Text = ""

cmbCourse.Text = ""

cmbCollege.Text = ""

txtPhone.Text = ""

txtSemester.Text = ""

loadList()

End Sub


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INSERT new data

Inserting new data to the table involves the use of SQL INSERT statement. Try the

following code to insert new data in the tblRegistration.

Private Sub cmdInsert_Click(ByVal sender As


cmdInsert.Click

strSql = "INSERT INTO tblRegistration VALUES('" &

txtMatricNo.Text & "','" & txtName.Text & "','" &

cmbCourse.Text & "','" & cmbCollege.Text & "','" &

txtPhone.Text & "','" & txtSemester.Text & "','" &

txtName.Text & "')"

Con.Execute(strSql)

loadList()

End Sub

Performing data search

Data search is being done by entering the required matric no in the matric no text box

and then pressing the search button. Search function involves the use of SQL

SELECT statemement with condition (in this case matric no is the condition).

Double click the cmdSearch button and write the following code:

Private Sub cmdSearch_Click(ByVal sender As


cmdSearch.Click

checkConn()

strSql = "SELECT * FROM tblRegistration WHERE

StudMatric='" & txtMatricNo.Text & "'"

rec1.Open(strSql, Con,

ADODB.CursorTypeEnum.adOpenStatic)

'assign each text boxes with specific fields

txtMatricNo.Text = rec1.Fields("StudMatric").Value

strStudMatric = txtMatricNo.Text

txtName.Text = rec1.Fields("StudName").Value

cmbCourse.Text = rec1.Fields("CourseCode").Value

cmbCollege.Text = rec1.Fields("StudCollege").Value

txtPhone.Text = rec1.Fields("StudPhone").Value

txtSemester.Text = rec1.Fields("StudSem").Value

End Sub


[78]

Chapter Exercise :

1. Complete the application by writing complete code for frmCourse and frmAdmin.


[79]

CHAPTER 5: DATA

REPORTING USING

REPORT VIEWER



Create a simple table

report

Apply data reporting

in Visual Basic 2008

using Report Viewer


[80]

5.0 DATA REPORTING USING REPORT VIEWER

Microsoft Report Viewer

This part shows how to create a simple table report based on the Sales database. You will add a report

template to your project, set up connection information for the Sales database, add a table data region, and

add a ReportViewer Windows Forms control to a Windows Form so the report can be viewed by users of the

application

5.1 Creating DataSet

Project Add New Item

In the Categories pane, choose Data.

In the Templates pane, choose DataSet.

In the Name box, type ProductDataSet and click Add.


[81]

View Server Explorer

Click at + Data Connections, Sales.accdb and Tables, so you will see the following figure.

Left click Product table (don’t release the mouse) and drag the Product table onto the design surface as

follows.


[82]

5.2 Creating Report

Project Add New Item

In the Categories pane, choose Reporting .

In the Templates pane, choose Report Wizard.

In the Name box, type Product Report.

Click Add.


[83]

You will see the following figure.

Click Next


[84]


Click Next


[85]


Click Next


[86]

In the Available fields pane, select all fields (press Shift key and select with your mouse).

Click Details> button.


[87]

Your report wizard should looks as follows.

Click Finish.


[88]


Click Finish


[89]

Your completed report looks as follows.


[90]

5.3 Creating Microsoft Report Viewer

Project Add Windows Form.

In the Name box, type ProductReportForm and click Add.

Enlarge the form as follows.

In the Toolbox, look for Reporting and double-click MicrosoftReportViewer.

Enlarge the ReportViewer as needed.

Open the smart tags panel of the ReportViewer control, by clicking the triangle on the top right corner of the

control. In the Choose Report drop-down list, select ProductReport.rdlc .


[91]

Test your report form.

Your report should display as follows.

To format Price field into currency.

Right-click the cell (the oval shape) and then click Properties.

Select the Format tab and click the browse (…) button to open the Choose Format dialog box


[92]

In the Format box, select Standard, select Currency, and then select a currency format.

Click OK, and then click OK again to close the Textbox Properties dialog box


[93]

Test your report form.

Your report should display as follows.

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