Alter Table -- Primary Key

Use the Primary Key page of the Alter Table notebook to define or alter the primary key for the table. A primary key is a column or set of columns that can be used to identify or access a particular row or rows. A primary key is a unique key, that is it is a key that is constrained so that no two of its values are equal. A table cannot have more than one primary key, and the columns of a primary key cannot contain null values. To change a new column to be nonnullable, use the Change Column window from the Columns page. You cannot change the nullable setting for an existing column.

You can define the primary key, add or drop columns from the primary key, or change the constraint name.

Tasks

• Defining the primary key
• Changing the primary key

Controls

• Available columns
• >, >>, <, <<
• Primary key columns
• Constraint name
• OK
• Cancel

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