Primary Keys and Unique Columns in Oracle and SQL-Server
The SQL-92 standard requires that all values in a primary key be unique and that the column not allow null values. Both Oracle and Microsoft SQL Server enforce uniqueness by automatically creating unique indexes whenever a PRIMARY KEY or UNIQUE constraint is defined. Additionally, primary key columns are automatically defined as NOT NULL. Only one primary key is allowed per table.
Views: 1502 | 
| by Jason
View this tutorial
Most popular (last 7 days)
Ciara forum signature
Water in Cinema 4D
Hologram
Star Wars Hailfire Droid
Create a computer case model
Highest rated (last 7 days)
Creating an AS3 XML Video Player in Flash
Using Business Rules to Define Decision Points
Creating Panoramic Images with AgileVR
Adding text to an image in memory
Psychedelic logo