Using Constraints, Defaults, and Null Values

Planning tables requires identifying valid values for a column and deciding how to enforce the integrity of the data in the column. Microsoft® SQL Server™ 2000 provides several mechanisms to enforce the integrity of the data in a column:

• PRIMARY KEY constraints
  
  
• FOREIGN KEY constraints
  
  
• UNIQUE constraints
  
  
• CHECK constraints
  
  
• DEFAULT definitions
  
  
• Nullability

See Also

Data Integrity