Planning a Database

Ms. Lara Jo F. Boongaling

The most important step in creating a database that works.

Remember!A poor plan and design can make it

difficult, or even impossible, to manipulate and control data.

Planning

1. Know the purpose of your database- So you can decide what information will go

into it. If you wish to create a database of your classmates’ personal information, start planning what fields to include into it.

Before you create a database you should consider the following:

2. Gather all reports you will need for the database

- Gathering all details or information about your subject will help you start creating the list of fields you need.

Before you create a database you should consider the following:

3. Make a list of important fields you wish to include

- Decide if you really need all the information. If not, remove unnecessary fields or columns.

Before you create a database you should consider the following:

4. Check each field to see whether it should be split into additional fields based on how you need to sort, calculate or find information.

Before you create a database you should consider the following:

5. If you have more than one table, these tables should share their common fields. (all about relationships)

Before you create a database you should consider the following:

6. When you have finished identifying fields and tables, you are now ready to design and create tables, data types and field contents in your computer.

Before you create a database you should consider the following:

Designing a Database

1. Identify your purpose. Decide what kind of information you should include.

Example:Purpose or Project: To create a database of

classmates’ personal information.

Data needed: ?

After the planning stage you are now ready to design your database.

2. Gather data for the chosen fields.

After the planning stage you are now ready to design your database.

3. Filter or remove unnecessary field(s) or column(s) from the original database.

After the planning stage you are now ready to design your database.

The gender field is deleted.

4. Split needed or desired fields.

After the planning stage you are now ready to design your database.

The NAME Field Split into FIRST NAME and LAST NAME fields

Defining Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

1. Text- This type of data accepts any normal

character and is limited to a field length of 255, including spaces. It is use to store alphanumeric characters for entering text, numbers, or a combination of both, but accepts only numbers not for computation.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

2. Memo- This is used for entering and storing lengthy

text fields such as extended descriptions, explanations or comments. A memo field may contain 64 000 characters in MS Access 97 and 65 535 characters in MS Access 2000.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

3. Number- This type of data accepts numeric data,

which performs mathematical calculation. The number of decimal places may be specified in this option.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

4. Date / Time- This is a special type of number data type for

entering the date and time information. With this, you can find the number of days between dates.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

5. Currency- This is also a special type of Number data

type which fixes a certain number of decimal places for monetary information. Currency values and numeric data used in mathematical calculation involve data with 1 to 14 decimal places.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

6. Auto Number- With this data type, MS Access automatically

supplies sequential numbers to records as you enter them if property is set to ‘Increment’. If you have set it to ‘Random’, MS Access will automatically generate a new number for each new record.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

7. YES / NO- Accepts only a value that has either yes or

no, true or false, or on or off format. You can use these formats depending on the information you wish to represent in a particular field.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

8. OLE (Object Linking and Embedding)- Enables you to either link or embed an object

created in another application program.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

9. Hyperlink- MS Access helps the user store addresses in

Web documents, network files, and local files.

Data Types

Determine the type of data and range of values that can be entered in a field. MS Access allows the following data types:

10. Lookup Wizard- Allows you to look up values previously

entered in another database object. This helps you choose a value from another table or from a list of values.

Data Types

Database Structure

You are now in the last step of designing before creating the actual database in your computer

using the DBMS tool in MS Access

A sample database structure

Database Table

A sample database table