Computed columns are columns that contain data determined by data in other columns.
For example, an
Employee_Salary
table contains columns
Emp_ID
,
Basic_Salary
,
Allowances
,
Tax_Deduction
, and
Net_Pay
.
Net_Pay
is a computed column that is calculated as
Basic_Salary + Allowances - Tax_Deduction
. The database populates the data in
Net_Pay
. If the values in any of the three columns change, the database updates the value in the
Net_Pay
column.
You can include tables that contain computed columns in a TDM operation. Because the values are calculated based on data in other columns, the TDM operation does not copy data into computed columns in the target. The database populates the values based on the data in other columns.
You cannot apply data masking or data generation rules on computed columns. You cannot create a value cascade or an auto cascade on computed columns.
You cannot perform data generation operations that include an entity if the primary key column is a computed column.