A key specification (key_spec) allows table rows to be located whose key column values match the values in the key specification. A row with the specified key values does not have to exist.
The value specification value_spec must not be NULL.
The column name column_name must identify a key column in the table.
The key specification must contain all the key columns in a table. The individual key specifications key_spec must be separated by commas.
For tables defined without key columns, an implicitly generated column exists – SYSKEY CHAR(8) BYTE, which contains a key integrated by the database system. This column can be used in a key specification.
A key specification is used in the following SQL statements: