The RESTRICT Keyword

The RESTRICT keyword is required with the DROP ROW TYPE statement. RESTRICT causes DROP ROW TYPE to fail if dependencies on row_type exist.

The DROP ROW TYPE statement fails and returns an error message if any of the following conditions is true:
  • The named ROW data type is used for an existing table or column.

    Check the systables and syscolumns system catalog tables to find out whether any tables or data types use the named ROW data type.

  • The named ROW data type is the supertype in an inheritance hierarchy.

    Look in the sysinherits system catalog table to see which named ROW data types have child types.

The following statement drops the named ROW data type employee_t: 
DROP ROW TYPE employee_t RESTRICT