DATABASE MANAGEMENT II

Database packages are used to design a database in a computer. Example of a common database package is Microsoft Access. MS Access is a Relational Database Management System used to create and modify databases.

USING MS- ACCESS FOR DATABASE

To create a database on the computer with MS Access

Load MS Access: do the following;

Click on the Start Menu
Point to All program
Point to Microsoft Office
Click on Microsoft office Access

Creating Database

From the displayed window, click on blank database.
By the right hand side of the windows, where the arrow is pointing in the picture-screen above, click inside the file name text box and type the desired database name.
Click on Create command button. A database with the filename given will be created

Files are created as tables in the database

Creating a file

Click on Create menu and select Table
At all Tables tab, right click on any of the table.
Select design View

In the Save As dialog box, type a desired table name (e.g. Student Table) in the Table Name text box and click ok.

Tables in database on a computer are composed of rows and columns. A table in MS Access is organized into rows and columns like the picture screen shown below.

A row contains records or diverse fields. The rows specify the number of records in the table. For example, in the picture-screen above, there are six records in the student table.

A column usually represents a field in a database table. It contains specify the type of information. For example, in the picture screen above, there are three fields (data fields), REG. No., Surname, and first name.

EVALUATION

List the steps on how to lad MS-Access.
How do you create database using Ms- Access

Create Fields with Data Types

Fields are assigned field names relevant to the information they keep. Field names are assigned data types which determine the kind of data they accept as input. For example in MS Access table above, Surname are alphabetic, the fields will not accept numeric (numbers) inputs 10 or 500 as surname. To set data type for field in MS Access, follow the steps below;

After creating the table in design view under the field name tab, then type the field name and under the data type tab next to the field name, click the drop down menu and select AutoNumber as shown below.

For example, using the above picture screen, the field name ID Number will be assigned Number data type since the ID Numbers will be numeric. In the same way, TEXT data type will be assigned to Surname and First name.

Unique Identifier

A table contains a unique identifier i.e. a KEY. In MS Access, a default primary key is usually specified for the first field. To set another field of your choice as primary key, right click on the first cell and select Primary Key.

Note: The symbol of a key should appear beside the field, after setting that field as a unique identifier. If it does not appear repeat previous steps.

Creating Database

Generally, creating database using any DBMS entails the following basic steps:

Define the Database Structure

The database structure specifies the type of database organization that should be used. If the relational form is selected, the database structure will include RDBMS, structure of table, number of rows, number of columns, the key, and relationship of the database etc.

Specify Field Type

When a database is being created, all fields are set to accept a particular type of input by specifying a field type. A field type is also known as a Data type. The essence of a data type is to prevent a wrong input from being stored in a database (i.e. database integrity). Usually the name of a data type varies with DBMS but portrays a general meaning. These include;

Alpha numeric/ text field: Fields that accepts both numbers and text e.g. ASP2548.
Numeric Fields: Fields that accepts numbers in two forms: Real number i.e. decimal numbers e.g. 8.15, 9.1 and integers’ i.e. whole numbers e.g. 125, 80 etc.
Date Fields: They store data in date format e.g. 11-04-2009
Boolean fields: The data accepted by these fields are either Yes/No or True/False.
Memo: Long text. Use for long pieces of text. Such as notes and long description. Can store up to 64,000 characters.
Currency: Use for currency.
AutoNumber: Unique sequential numbers or random number automatically inserted when you create a record. Use to create primary key.
Hyperlink: Use to store hyperlink
Attachment: use to store attachments e.g files, images etc.
OLE Object: Use to attach an OLE object such as word document, Spreadsheet, or PowerPoint Presentation

GENERAL EVALUATION

Define the Database Structure.
What is unique identifier?
What is Hyperlink?

WEEKEND ASSIGNMENT

Another name for field type is known as ___ A. file type B. name typeC.record type D. data type
Another name for unique identifier is known as ___ A. key B. dataC. field D. record
___ is an attribute or field that can be used to identify a record in a database table or file. A. data B. field C. key D. table
___ is used to design a database in a computer. A. Database package B. Graphics package C. Spreadsheet package D. Word Processing package
The data accepted by these fields are either Yes/No or True/False is ___ A. primary key B. Boolean fields C. Data D. None

THEORY

Define database Model.
List and explain types of database Model.
All fields are set to accept a particular type of input, list and explain the data types.