Tuesday, December 25, 2012

Planning a Database

Turn off the computer

This way you can get rid of the distraction of the program.

Purpose Statement


     ·   “I want to keep track of employee personal and payroll information, training and benefits.”
     ·   “I want to keep track of client information, our products, and the products that the clients buy.”
     ·   “I want to keep track of the data we gather on ________ and how we service those items.”
     ·   “I want to keep track of the items in my house, which room it’s in and the warranty information.”

Collect current data


     ·   Forms your employees, clients and vendors are filling out.
     ·   Databases/tables you are storing information
o   Employees/Clients
o   Billing
o   Invoices
o   Training/Benefits

Brainstorm field names.

     ·   Field names are the name of the columns of the tables.
     ·   Some used but not needed
     ·   Some needed but not used

Group Information into Tables

     ·   Employee information
     ·   Client information
     ·   Benefit information
     ·   Invoice information
     ·   Details of the invoices
     ·   Product information

Normalize!

3.2 Rules of Normalization
      ·   Atomize
      ·   No Redundancy
o   Dependencies
o   No Blanks
o   Relationships

Rules of Normalization Explained

Rule #1 Atomize

     ·   Smallest meaningful value.
o    First name
o    Last name
o    Today’s date
o    Birth date

Rule #2 No Redundancy

     ·   Repeated Values?
o    Dates
o    Names
     ·   DB run faster

Rule #3 Dependencies

     ·   Primary Key!
o    UNIQUE
o    required
     ·   Helps Access keep record separated

No Blanks

     ·   Blanks waste space
     ·   Needed for
o    Middle Initial
o    Suffix
o    Address line #2

Relationships

     ·   How do the Tables fit together?
     ·   Primary and foreign keys

Properties

     ·   Define properties for fields such as:
o    Data type
o    Field size
o    Input masks
o    Default values
o    Captions

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