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Database design. Using Access 2007. Access 2007. DMS Database management system Database Collection of data organized in a manner that allows access, retrieval, and use of that data. --- OR --- A place to store data and retrieve information. Access Objects…. - PowerPoint PPT Presentation
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DATABASE DESIGN
Using Access 2007
ACCESS 2007 DMS
Database management system Database
Collection of data organized in a manner that allows access, retrieval, and use of that data.
--- OR ---A place to store data and retrieve
information
ACCESS OBJECTS… Tables
Like ExcelEnter, edit, and delete dataDisplay, sort and filter
QueriesAsk questions and get answers from data
ReportsPrint customized displays of data
FormsVisualCan limit data by user
TABLES Each row is a separate record, or an entry in the
database One customer One order
Each record has a unique identifier, called a primary key, such as:
Customer ID Student ID SSN
Each column is a field Name, address, phone number Item number, quantity ordered
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 would 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 TABLES1. Decide what tables to including in your
database. 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
Orders Customer number, item number, quantity
STEPS FOR DESIGNING TABLES2. Choose a primary key for each table3. Format the data for each field
Text or numbers Maximum number of characters Required or not?
4. Security – who will have access5. Set relationships between tables
COMMON ACCESS DATA TYPES Text fields (default)
May contain letters, numbers, and symbolsMaximum 255 characters
Number fieldsMay contains ONLY numbersCan be positive or negativeCan be used for arithmetic operations
Currency fieldsMay contain ONLY monetary dataWill display like currency formatting in ExcelCan be used in arithmetic operations
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
storage Decimal: More decimal places; 3x the
storage Replication ID: Special identifier required
for replicationChoose 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 record Values CANNOT be re-used
Yes/No Values 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 applicationsAll tables, queries, forms and reports are
stored in the same fileWhen you start a new database, you have to
name it before you can create any tablesAccess saves database files with an .accdb
extensionWhen 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.