Date post: | 27-Dec-2015 |
Category: |
Documents |
Upload: | dominic-shepherd |
View: | 221 times |
Download: | 0 times |
Databases
CHAPTER 10
Chapter 10: Databases 2
10 Databases and Structured Fields A database is a
collection of information– Typically stored as
computer files
A structured file uses a uniform format to store data in the file
Chapter 10: Databases 3
10 Fields
Contain the smallest unit of meaningful information
Each field has a unique field name Variable-length field vs. fixed-length field
Chapter 10: Databases 4
10 Records
Collections of data fields
Records can be displayed as rows in a table or as forms.
Chapter 10: Databases 5
10 Records
Each kind of record is referred to as a record type
Chapter 10: Databases 6
10 Records
A record that contains data is referred to as a record occurrence
Chapter 10: Databases 7
10 Relationships and Cardinality
A flat file is a structured file that contains only one record type
A relationship is an association between data that is stored in different record types
Chapter 10: Databases 8
10 Relationships and Cardinality
Cardinality refers to the number of associations that can exist between two record types
Chapter 10: Databases 9
10 Hierarchical, Network, Relational, and Object-Oriented Databases
A hierarchical databases arranges record types in a hierarchy
Chapter 10: Databases 10
10 Hierarchical, Network, Relational, and Object-Oriented Databases
The network database model allows many-to-many relationships in addition to one-to-many relationship
Chapter 10: Databases 11
10 Hierarchical, Network, Relational, and Object-Oriented Databases
A relational database stores data in a collection of related tables
Chapter 10: Databases 12
10 Hierarchical, Network, Relational, and Object-Oriented Databases
An object-oriented database stores data as objects, which can be grouped into classes and defined by attributes and methods
Chapter 10: Databases 13
10 Data Management Software
Microsoft Word allowsyou to create a table ofinformation, such as amailing list, which youcan edit, sort, search,and print. In addition,you can merge data fromthe table with a templateletter to create form letters,mailing labels, andenvelopes.
CLICK TO START
Chapter 10: Databases 14
10 Data Management Software
Chapter 10: Databases 15
10 Data Management Software
It is possible to enter data as an ASCII text file
Custom data management software Data dependence vs. data independence
Chapter 10: Databases 16
10 Database Management Systems
Chapter 10: Databases 17
10 Database Management Systems
Database client software allows any remote computer or network workstation to access data in a database
Chapter 10: Databases 18
10 Database Management Systems
Multiple users can interact with the same database
Chapter 10: Databases 19
10 Databases and the Web
The Web provides opportunities and challenges for accessing databases– Static Web publishing– Dynamic Web publishing
• Server-side program
Chapter 10: Databases 20
10 Databases and the Web
Chapter 10: Databases 21
10 Databases and the Web
Forms can collect data, as well as specifications for a query– XForms
Chapter 10: Databases 22
10 Databases and the Web
Several tools are available to help create server-side programs
Chapter 10: Databases 23
10 XML Documents
Markup language allowing field tags, data, and tables to be incorporated into a Web document
Chapter 10: Databases 24
10 XML Documents
Used to specify a standard structure of fields and records
Data in an XML document is searchable XML is portable, but not optimized for many
common database operations– Consider storing data in a relational database,
managing it with RDBMS software, and generating XML documents for exchanging data over the Web
Chapter 10: Databases 25
10 Defining Fields
The term database structure refers to the arrangement of fields, tables, and relationships in a database
Store last names and first names in separate fields
Use a primary key field to make each record unique
Use appropriate data types for each field
Chapter 10: Databases 26
10 Defining Fields
Chapter 10: Databases 27
10 Defining Fields A computed field is a calculation that a DBMS
performs during processing and stores temporarily
Uppercase and lowercase are not always treated the same– Case sensitive database
Use field formats to show what the data is supposed to look like when it’s entered
Use field validation rules to filter data
Chapter 10: Databases 28
10 Normalization
Process that helps save storage space and increase processing efficiency– Reduces data redundancy
Chapter 10: Databases 29
10 Organizing Records
Records can be organized in different ways, depending on use
Sorting– A table’s sort order refers to the order in which
records are stored on disk– Sort key
Indexing– Similar to the index in a book
Chapter 10: Databases 30
10 Organizing Records
When indexed by date, the index file contains a list of keys and the record number (R#)that contains more information about the album released onthat date.
Chapter 10: Databases 31
10 Designing the Interface
Arrange fields in a logical order Provide visual clues to the entry areas Entry areas should appear in a consistent
position relative to their labels Provide a quick way to move through the
fields in order
Chapter 10: Databases 32
10 Designing the Interface
Use scrolling to create multiple screens, if necessary
Provide buttons or other easy-to-use controls for navigating through records
Supply on-screen instructions
Chapter 10: Databases 33
10 Designing the Interface
Chapter 10: Databases 34
10 Designing Report Templates
Report generators are used to specify the content and format for a database report
A report template contains the outline or general specifications for a report
Chapter 10: Databases 35
10 Designing Report Templates
Supply only the information required Present information in a usable format Information should be timely Information should be presented in a clear,
unambiguous format Present information in the format most
appropriate for the audience
Chapter 10: Databases 36
10 Loading Data
Data can be loaded into a database by:– Using generic data entry tools– Using a customized data entry module
A conversion routine converts the data from its current format into a format that can be automatically incorporated into the new database
Chapter 10: Databases 37
10 SQL Basics
Intermediary between the database client software and the database itself
Chapter 10: Databases 38
10 SQL Basics
Chapter 10: Databases 39
10 Adding Records
Chapter 10: Databases 40
10 Searching for Information
SELECT AlbumTitle, AlbumCover FROM Albums
WHERE ArtistName = ‘Jefferson Airplane’
The AND, OR, and NOT Boolean operators are used to perform complex SQL searches
The use of parentheses indicates the part of the query to perform first
Chapter 10: Databases 41
10 Updating Fields
UPDATE Albums
SET InStock = InStock – 1
WHERE AlbumTitle = ‘G.I. Blues’
Global updates change the data in multiple records simultaneously– Works only for records with similar characteristics
Chapter 10: Databases 42
10 Joining Tables
Joining tables in SQL allows you to create relationships between tables
Chapter 10: Databases 43
10 Lab Assignment-Create 3 Database Tables
You are a DBA at Wal-Mart Superstore and you need to create three new database tables for all the items you sell in Excel– Divide the store into 3 sections. Create 1 table
per worksheet for each section. Name the worksheets after each section you create.
– Create all the proper and logical field columns that will be used for each section.
– Fill in the first 3 records for each table with random materials found in that section.