View stunning SlideShares in full-screen with the new iOS app!Introducing SlideShare for AndroidExplore all your favorite topics in the SlideShare appGet the SlideShare app to Save for Later — even offline
View stunning SlideShares in full-screen with the new Android app!View stunning SlideShares in full-screen with the new iOS app!
E. F. Codd, who was the IBM researcher credited with the creation and evolution of the relational database, set forth a set of rules that define how data should be organized in a relational database. Initially, he proposed three sequential forms to classify data in a database:
After these initial normal forms were developed, research indicated that they could result in update anomalies, so three additional forms were developed to deal with these issues: fourth normal form (4NF), fifth normal form (5NF), and the Boyce-Codd normal form (BCNF). There has been research into a sixth normal form (6NF); this normal form has to do with temporal databases and is outside the scope of this discussion.
Atribut Z pada relasi R dikatakan tergantung transitif pada atribut X , jika atribut Y tergantung pada atribut X pada relasi R dan atribut Z tergantung pada atribut Y pada relasi R. ( X Y, Y Z , maka X Z )
Normalization improves the efficiency of inserting, updating, or deleting data. The fewer places the data has to be updated, the more efficient the update and the greater the data integrity.
Denormalization improves the efficiency of reading or selecting data and reduces the number of tables the data engine has to access or the number of calculations it has to perform to provide information.