Visual Database Tools
Working with Constraints
Constraints are rules that the database server enforces for you. For more information see Constraints.
For details about working with constraints, see the following topics:
| To | See |
|---|---|
| Attach a check constraint to a table to specify the data values that are acceptable in one or more columns | Attaching a New Check Constraint to a Table or Column |
| Create a constraint expression to check data for a condition | Defining a Check Constraint Expression |
| Change the constraint expression or the options that enable or disable the constraint for specific conditions | Modifying a Check Constraint |
| Apply constraints either to new data only or to existing data as well | Checking Existing Data When Creating a Check Constraint |
| Disable a check constraint when data is added to, updated in, or deleted from a table | Disabling a Check Constraint with INSERT and UPDATE Statements |
| Disable a check constraint when your table is replicated in another database | Disabling a Check Constraint for Replication |
| Remove the limitations on data values in a column | Deleting a Check Constraint |
| Ensure no duplicate values are entered in specific columns | Creating a Unique Constraint |
| Change the columns that the constraint is attached to, change the constraint name, or set additional properties for the constraint | Modifying a Unique Constraint |
| Remove the requirement for uniqueness for values entered in the column | Deleting a Unique Constraint |
| Enforce uniqueness for values entered in specified columns | Defining a Primary Key |
| Change the column order, index name, clustered option, or fill factor | Modifying a Primary Key |
| Copy column properties from a primary key column to a foreign key column to relate the two columns | Copying Column Properties to a Foreign Key Column |
| Remove the requirement for uniqueness for the values entered in a column | Deleting a Primary Key Constraint |
| See which columns participate in the foreign key side of a relationship | Viewing Foreign Key Attributes |
| Change which columns are related to columns in the primary key table | Modifying a Foreign Key |
| Check existing data when creating a relationship | Checking Existing Data when Creating a Relationship |
| Disable a foreign key constraint during INSERT and UPDATE transactions | Disabling a Foreign Key Constraint with INSERT and UPDATE Statements |
| Disable a foreign key constraint during replication of the table | Disabling a Foreign Key Constraint for Replication |
| Remove the requirement to enforce referential integrity between primary key columns and the related columns in another table | Deleting a Foreign Key Constraint |