Rule Object

The Rule object exposes the attributes of a single Microsoft® SQL Server™ data-integrity rule.

Properties

CreateDate Property	Owner Property (Database Objects)
ID Property	Text Property
Name Property

Methods

Remarks

SQL Server offers several mechanisms for ensuring data integrity. A SQL Server rule is a Transact-SQL condition_expression syntax element that defines a data-integrity constraint. A rule can be bound to a column or user-defined data type. condition_expression is executed to validate data for a single column when a value is inserted into the column bound by the rule. For more information, see CREATE RULE.

With the Rule object, you can:

• Create a SQL Server rule that defines an integrity constraint.
  
  
• Bind an existing SQL Server rule to a column or user-defined data type.
  
  
• Remove the constraint from a column or user-defined data type by unbinding a SQL Server rule.
  
  
• Remove a SQL Server rule definition from a SQL Server database.
  
  
• Generate a Transact-SQL script to create the rule represented by the object.

The Name property of a Rule object uses the SQL Server data type sysname. The value of the Name property must be unique for a database.

After you have created the rule, use the BindToColumn and BindToDatatype methods of the Rule object to apply the constraint to SQL Server columns and user-defined data types.

To create a SQL Server rule

1. Create a Rule object.
   
   
2. Set the Name property.
   
   
3. Set the Text property with the Transact-SQL script that validates data integrity for the columns bound by the rule.
   
   
4. Add the Rule object to the Rules collection of a connected Database object.

To remove a rule from a SQL Server database

1. Get the referring Rule object from the Rules collection of a connected Database object.
   
   
2. Use the ListBoundColumns and ListBoundDatatypes methods to determine affected SQL Server columns and user-defined data types.
   
   
3. Use the UnbindFromColumn and UnbindFromDatatype methods to remove the constraint from columns and user-defined data types bound by the rule.
   
   
4. Use the Remove method of the Rule object to remove it from the SQL Server database.

   Note  The Rule object is compatible with instances of SQL Server 2000 and SQL Server version 7.0. However, the Rule2 object extends the functionality of the Rule object for use with features that are new in SQL Server 2000.

See Also