9.1 Basic Concepts of Database• The Structure of a Database
– A database is a structured collection of data and consists of one or more tables.
– A table in turn contains records and fields. A record is a row which contains a set of properties related to a particular item while a field is a column which contains a specific property for all items.
– A well-designed database enables huge data storage and efficient data retrieval.
9.1 Basic Concepts of Database• The Structure of a Database
Structure of a database
9.1 Basic Concepts of Database• Primary Key
– A primary key is a field or a set of fields in a table.
– Each record’s primary key is a unique value for identifying itself among all the records in the same table.
– Primary keys can be used to establish relationships among tables.
– In the following table, the field ‘Student ID’ can be used as a primary key since all the students are assigned a unique student identity number.
9.1 Basic Concepts of Database• Primary Key
Student ID
Student name
Class Class number
Age Sex
010101 Chan Tai Man
3A 3 15 M
010112 Cheung Siu Ming
3A 6 14 M
010215 Fok Wing Sze
3B 10 15 F
010231 Leung Hon
Cheung
3B 18 15 M
010345 Wong Fung Yi
3C 33 16 F
A table of students’ information
Primary key
9.1 Basic Concepts of Database• Primary Key
Student ID
Student name
Class Class number
Age Sex
010101 Chan Tai Man
3A 3 15 M
010112 Cheung Siu Ming
3A 6 14 M
010215 Fok Wing Sze
3B 10 15 F
010231 Leung Hon
Cheung
3B 18 15 M
010345 Wong Fung Yi
3C 33 16 F
A table of students’ information
Primary key
9.2 Using Database Software– When we manipulate a large amount of
data, manual processing is proved to be both tedious and inefficient.
– Therefore, we need to use database software to process database records.
– With database software, relevant information can be accessed and updated efficiently with built-in functions– sorting– searching – report generation
9.2 Using Database Software– Common database software
– Microsoft Access– FoxPro– Oracle– MySQL
– They have different processing capacities that fit into different scales of applications.
• Working Environment of Microsoft Access– In Microsoft Access, the database window enables
users to create various objects in the database.– After an object is created, it can be accessed in this
window.
9.2 Using Database Software
The working environment of Microsoft Access
Title bar
Toolbar
Objects column
Creation mode
Existing objects
• Tables– A database can consist of multiple tables which
are structured collections of records.– Each record is one single row in a table and each
record consists of many fields.
9.2 Using Database Software
An example of a table
• Query– A set of user-defined criteria for retrieving the
relevant information from the database– It must be written in a specific format. Microsoft
Access provides different tools to help users compose a query.
– After a query is submitted, the requested data will be retrieved and the result will be displayed to users.
9.2 Using Database Software
A query in design (left) and its executed result (right)
• Form– An interface created by users to manipulate and
display data– It can also serve other purposes such as user
menus and message display.
9.2 Using Database Software
An example of a form
• Report– Present information in a user-defined format.– It can be viewed on screen or printed on paper.
9.2 Using Database Software
An example of a report in the Print Preview
• Views of Objects– In Microsoft Access, each object can be displayed
in different ways with different views.
9.2 Using Database Software
Objects ViewsTables Design View, Datasheet View, Pivot Table View
and Pivot Chart View
Queries Design View, Datasheet View, SQL View, Pivot Table View and Pivot Chart View
Forms Design View, Datasheet View, Form View, Pivot Table View and Pivot Chart View
Reports Design View and Print Preview
List of different views for different objects
• Views of Objects
9.2 Using Database Software
A table in the Design View
The Datasheet View
• Views of Objects
9.2 Using Database Software
A table in the Design View
The Datasheet View
9.3 Creating a Table in Microsoft Access
• Methods of Creating a Table– In Microsoft Access, there are three ways to
create a table in a database.•By using the Design View;•By using the Table Wizard;•By entering data into Datasheet.
– Using the Design View is the most preferred method to create a table since it allows users to define precisely the properties of each field such as name, data type and size.
9.3 Creating a Table in Microsoft Access
• Methods of Creating a Table– The other two methods only allow users to create
tables of rough designs and sooner or later, the table structures will probably need to be refined in the Design View anyway.
– It is always a good practice to design thoroughly first before implementation and therefore the latter two methods are not recommended to build a robust database.
9.3 Creating a Table in Microsoft Access
• Creating a Table in Design View– The Design View window is divided into two parts
• Top pane– Enter the field names, data types and an optional
description of the fields.
• Bottom pane– Specify field properties.
Working environment in Design View
Top pane
Bottom pane
9.3 Creating a Table in Microsoft Access
• Creating a Table in Design View– The Design View window is divided into two parts
• Top pane– Enter the field names, data types and an optional
description of the fields.
• Bottom pane– Specify field properties.
Working environment in Design View
Top pane
Bottom pane
