Defining a Database Using SQL › Defining a CALC Key

Defining a CALC Key

You create a CALC key by issuing the CREATE CALC statement and specifying a CALC key column.

Things You Can Specify

1. Whether the CALC key is unique
2. Name of the table associated with this CALC key
3. Name of the column or columns that make up the CALC key

Considerations

• You can define only one CALC key for a table.
• The table must be empty when you define a CALC key for it.
• You must specify NOT NULL for the column(s) on which the CALC key is placed if you use the UNIQUE option.
• The table cannot be the referencing table in a clustered referential constraint.
• The table cannot have a clustered index defined on it.

Examples

In the following example, a unique CALC key is defined on the EMPLOYEE table. The CALC key consists of one column, EMP_ID.

create unique calc key on prod.employee(emp_id);

In the following example, a unique multi-column CALC key is defined on the BENEFITS table. The CALC key consists of two columns, EMP_ID and FISCAL_YEAR.

create unique calc key on test.benefits(emp_id, fiscal_year);