1 – DATA_DEFINITION
Syntax options: DATA DEFINITION | READ | WRITE See the SET TRANSACTION statement for a description of the arguments.
2 – lock_mode
Syntax options: IN lock-mode MODE | FOR lock-mode MODE Specifies the lock mode to be used for the specified tables and views. The IN and FOR keywords are synonymous. A table lock mode can be promoted, but cannot be demoted. For example, you can promote a SHARED READ lock to SHARED WRITE, but you cannot demote a SHARED WRITE mode to a SHARED READ mode. See the SET TRANSACTION statement for a description of these arguments.
3 – table-name
The names of one or more tables or views currently existing in the database that you want to lock and reserve. You can specify tables created as GLOBAL or LOCAL TEMPORARY TABLES, but they will be ignored because these types of tables do not contain shared data and so are never locked. You can specify tables from multiple databases by using the alias name as a prefix to the table name. If you do not specify an alias, then the default alias is used.
4 – wait-mode
Syntax options: WAIT | NOWAIT | DEFAULT WAIT Specifies what the LOCK TABLE statement does when it encounters a locked table. If you specify WAIT, the statement waits for other transactions to complete and then proceeds. If you specify NOWAIT, your transaction returns an error message when it encounters a locked table. If you specify DEFAULT WAIT, then the lock mode specified for the current transaction is used. If you specify a different lock mode than was specified for the transaction, the mode you specify with the LOCK TABLE statement takes precedence, unless the table is already reserved. The WAIT clause is the default.