DATABASE D

ESIGN

USING M

ICROSOFT

ACCESS

What is a Database?

DMSDatabase management system

DatabaseCollection of data organized in a manner that allows access, retrieval, and use of that data. --- OR ---A place to store data and retrieve information

DATABASE D

ESIGN

USING A

CCESS 2007

ACCESS OBJECTS…

Each row is a separate record, or an entry in the database

One customerOne order

Each record has a unique identifier, called a primary key, such as:

Customer IDStudent IDSSN

Each column is a fieldName, address, phone numberItem number, quantity ordered

TABLES

THE KEY

To designing a good database ….

A good plan

NORMALIZING DATA

Table designs should eliminate redundant (repeating) data. This is called normalizing a database.

Customer names and addresses should be listed in a separate table, and not included with every order the customer makes

Students’ names and address are in a separate table, and not included with their schedule and grade information

More info on database design for Access 2007 is available here.

STEPS FOR DESIGNING TABLES

What tables? An online clothing store might include:Product inventory

Item number, Item name, purchase price, number in stock

Vendors (the people you buy from)Vendor number, vendor name, address, city, state, zip, terms

Customers (the people you sell to)Customer number, customer, name, address, city, state, zip, phone number

OrdersCustomer number, item number, quantity

STEPS FOR DESIGNING TABLES

Choose a primary key for each table Format the data for each field

Text or numbers Maximum number of characters Required or not?

Security – who will have access? Set relationships between tables

COMMON ACCESS DATA TYPES

NUMBER FIELDS

Byte: Integer from 0 to 255 Integer: Integers from -32,768 to 32,767 Long Integer: Integers from -2,147,483,648 to

2,147,483,647. Single: Numbers with up to 7 decimal places Double: More decimal places; 2x the storageDecimal:

More decimal places; 3x the storage Replication ID: Special identifier required for

replication

Choose the smallest size you can for your data

OTHER ACCESS DATA TYPES Memo

Up to 63,999 characters Date/Time AutoNumber

Stores a unique sequential number for each recordValues CANNOT be re-used

Yes/NoValues can be Yes/No, True/False, or On/Off

OLE Object Hyperlink Attachment

Images, spreadsheets, etc.

RELATIONSHIPS

Relationships exists between tables One-to-many (most common)

Each customer has many ordersEach student has many classesEach employee has many paychecks

One-to-oneEach customer has one addressEach student has one lockerEach employee works for one department

Many-to-many (least common)

FACTS ABOUT ACCESS 2007

Field names Can have up to 64 charactersCan contain letters, numbers, characters and spaces

EXCEPT Periods (.)Exclamation points (!)Accent graves (`) Square brackets ([ and ])

USING ACCESS

Some things about Access are different from other Office applications

All tables, queries, forms and reports are stored in the same file

When you start a new database, you have to name it before you can create any tables

Access saves database files with an .accdb extension When you enter data, each record is automatically

saved when you move to the next If you delete a record or a table field, it gone for good

(older versions).

THE ACCESS WINDOW