Normalization

Normalization

1. Purposes

   • organizing of attributes and relations
   • minimizes data redundancies
   • Issues?
     • Delete anomilies
       • Deletng critical info
     • Update Anomilies
       • Update data at 1 table only
     • Insert Anomilies
       • Error when inserting data
   • Functional Dependancy
     • Partial
       • attribute that depends on a part of a PK
       • occurs when composite PK exists
     • Transitive
       • a non PK that depends on another non PK

2. Process

   • UNF - 1NF
     • eliminate repeating group
     • identify dependancy
   • 1NF - 2NF
     • remove partial dependancies
     • split tables
   • 2NF - 3NF
     • remove transitive dependancies
     • split tables again