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Book 1

• Chapter 1
• Chapter 2
• Chapter 3
• Chapter 4
• Chapter 5
• Chapter 6
• Chapter 7
• Chapter 8
• Chapter 9
• Chapter 10
• Chapter 11
• Chapter 12
• Chapter 13
• Chapter 14
• Chapter 15
• Chapter 16/17
• Chapter 18/19
• Chapter 20
• Chapter 21
• Chapter 22/23

Book 2

• Chapter 1
• Chapter 2
• Chapter 3
• Chapter 4
• Chapter 5
• Chapter 6
• Chapter 7
• Chapter 9
• Chapter 10

Book 2 Ch. 7 Databases

Databases provide information storage. The information can be retrieved, in whole or in part, by a program designed to accept requests from users. A database can be housed in a single location, such as a PC or mainframe. It can also be constructed from multiple files and housed at different locations on the enterprise, this structure is known as distributed database.

Hypertext databases store information as objects. This information is useful for storing different types of information, such as text, images and multimedia. All data within this database is treated as objects, the data type is irrelevant. Any object within this database can be linked to any other object.

Schema is the structure of a database and often depicts the structure as a graphical reference. The schema defines tables and fields, and the relationship between them.

All database information is contained in tables. A table is a repository of information divided into columns and rows.

The table consists of fields (columns) and records (rows). A record include a complete set of information. A set of records is referred to as a file. The table also has field names by which information can be sorted and retrieved.

The information in a database can be accessed using a query. Queries can be thought of as questions from the user to the database table. The query returns a value. Queries include the following three general types:

• Menu query
  The user is offered a list of options from which to choose.
• Query by example
  The user states which fields and values are to be used in the query.
• Query language
  A specialized language called Structured Query language (SQL) is used to retrieve or manipulate information in the database.

Query languages come in four flavors:

• First generation
  Machine language.
• Second generation
  Assembly language.
• Third generation
  High level programming language (Java, C++)
• Fourth generation
  More closely resembles verbal language

A Database Management System is an application that allows users to manipulate information in the database. This includes:

• Flat-file
  Stores information on a single table consisting of multiple rows and columns.
• Relational database management system (RDBMS)
  Stores related information in a collection of tables.
• Multidimensional
  Use common field values and stores information in organized groups of records. This type of DBMS is usually generated from an RDBMS

DBMS includes the following technologies for access, storage and output of information:

• Open database Connectivity (ODBC)
  A standard method for accessing a database regardless of which DBMS or application is used. ODBC inserts a database driver as a middle layer between the DBMS and the application to translate requests and commands.
• ActiveX Data Objects (ADO)
  Used to access different information types, such as spreadsheets, web pages and other documents. ADO is one of the main components of Universal Data Access (UDA), a specification developed by Microsoft to access data regardless of its structure.
• Java Database Connectivity (JDBC)
  Executes SQL statements via Java programming to communicate with any SQL-compliant database. Developed by Sun.

Some common products used to store and manipulate database information:

• Oracle
• DB2
• Microsoft SQL server
• Paradox
• Filemaker Pro
• Lotus Domino
• Microsoft Access
• ASP
• Allair Cold Fusion
• Macromedia Dreamweaver Ultradev
• Pervasive Tango

Chapter 6 Book 2 Chapter 9 Book 2