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On-line Documentation

Keys


An integrity constraint is a rule that restricts the values in a database.

 

A unique constraint prohibits multiple rows from having the same value in the same column or combination of columns but allows some values to be null. A unique constraint designates a column as a unique key.

A primary key constraint combines a NOT NULL constraint and a unique constraint in a single declaration. It prohibits multiple rows from having the same value in the same column or combination of columns and prohibits values from being null. A Primary key constraint designates a column as the primary key of a table.

 

Table/view keys are managed within the Keys tab of Table Editor/View Editor.

 

Creating Keys

  • open the table/view in Table Editor/View Editor;
  • proceed to the Keys tab there;
  • right-click the tab area and select the New Primary/Unique context menu item;
  • edit the key properties using Key Editor.

 

Editing Keys

  • open the table/view in Table Editor/View Editor;
  • proceed to the Keys tab there;
  • right-click the key and select the Edit Primary/Unique Key context menu item, or simply double-click the key;
  • view the key properties using Key Editor.

 

Dropping Keys

  • open the table/view in Table Editor/View Editor;
  • proceed to the Keys tab there;
  • right-click the key and select the Drop Primary/Unique Key context menu item;
  • confirm dropping in the dialog window.