Table Editor - Constraints tab

On the Constraints tab, you can manage primary, foreign, and unique keys, and check constraints.

Constraints grid

The grid shows existing constraints and lets you add or remove them and view their details.

Add constraints

To add a constraint, right-click the grid and select one of the following options:

• Add Check Constraint – Creates a CHECK constraint.
• Add Foreign Key – Creates a foreign key.
• Add Primary Key – Creates a primary key.
• Add Unique Key – Creates a unique key.

Note

The following prefixes are added to the constraint name by default:

• PK_ – Indicates a primary key.
• FK_ – Indicates a foreign key.
• UQ_ – Indicates a unique key.
• CK_ – Indicates a check constraint.

Remove constraints

To remove a constraint, select it in the grid, right-click the grid, then select Remove Constraint. Alternatively, press Ctrl+Del.

View constraint details

The grid displays the following constraint details:

• Name – Displays a constraint name.
• Columns – Displays a column selected for the constraint.
• Constraint Type – Displays a constraint type.

Note

If a column already has a primary key, the Add Primary Key option is unavailable.

Constraint detail panels

When you select a constraint in the Constraints grid, the corresponding detail panel opens, where you can configure the constraint properties.

Check constraint detail panel

The following table describes the available properties.

Name	Description
Name	Enter a check constraint name.
Not valid	Select the checkbox to apply a constraint to new data without verifying existing rows.
Condition	Define a condition for a check constraint.

Note

Not valid is unavailable for new tables and for tables hosted on Amazon Redshift.

Foreign key detail panel

The following table describes the available settings.

Name	Description
Name	Enter a foreign key name.
Comment	Specify a foreign key description.
Update rule	Define the action to take when the referenced row is updated. The available options are NO ACTION, RESTRICT, CASCADE, SET NULL, and SET DEFAULT.
Delete rule	Define the action to take when the referenced row is deleted. The available options are NO ACTION, RESTRICT, CASCADE, SET NULL, and SET DEFAULT.
Referenced schema name	Select the schema that contains the referenced table or object. To update a list of schemas, click Refresh. Shortcut: Ctrl+R
Referenced table name	Select the parent table referenced by the foreign key. To update a list of tables, click Refresh. Shortcut: Ctrl+R
Options	Select the following options: Deferrable – to specify whether constraint checking can be deferred. Deferred – Select the checkbox to delay foreign key checking until the transaction is committed. Deferred is available only when Deferrable is selected.
Match	Select one of the following match types: Simple – Skips checking if any part of the key is NULL. Full – Requires all columns to be NULL or all columns to match. Partial – Verifies that at least one value is NULL.

Note

• You can’t change the name of an existing foreign key.
• Match is unavailable for Amazon Redshift.

Constraint columns

The following table describes the available properties.

Name	Description
Name	Select the constraint column.
Data Type	Indicates the data type of the constraint column.
Not Null	Indicates whether the constraint column is NOT NULL.
Remove	Removes the selected constraint column.
Move up	Moves the selected column up.
Move down	Moves the selected column down.

Referenced columns

The following table describes the available properties.

Name	Description
Name	Select the referenced column.
Data Type	Indicates the data type of the referenced column.
Unique	Indicates whether the referenced column contains unique values.
Primary	Indicates whether the referenced column is a primary key.
Remove	Removes the selected referenced column.
Move up	Moves the selected column up.
Move down	Moves the selected column down.

Primary key detail panel

The following table describes the available properties.

Name	Description
Name	Enter a primary key name.
Comment	Specify a primary key description.

Note

You can’t change the name of an existing primary key.

Primary key columns

The following table describes the settings for the primary key columns.

Name	Description
Name	Select the column you want to set as a primary key.
Data Type	View the data type of the column.
Not Null	View whether the column contains NOT NULL values.
Remove	Removes the selected column.
Move up	Moves the selected column up.
Move down	Moves the selected column down.

Unique key detail panel

The following table describes the available properties.

Name	Description
Name	Enter a unique key name.
Comment	Specify a unique key description.

Note

You can’t change the name of an existing unique key.

The following table describes the settings for the unique key columns.

Name	Description
Name	Select the column you want to set as unique.
Data Type	View the data type of the column.
Not Null	View whether the column contains NOT NULL values.
Remove	Removes the selected column.
Move up	Moves the selected column up.
Move down	Moves the selected column down.

For more information about indexes, or configuring their properties, see Table Editor - Indexes.