SET TRANSACTION Statement In read-only mode, it remains possible to change tables created with the  TEMPORARY  keyword using DML statements. Changes made with DDL statements are not permitted, just as with permanent tables. The  READ WRITE  and  READ ONLY  access modes also may be specified for an individual transaction using the  START TRANSACTION  statement. You can set transaction characteristics globally, for the current session, or for the next transaction only: A change to global transaction characteristics requires the  CONNECTION_ADMIN  privilege (or the deprecated  SUPER  privilege). Any session is free to change its session characteristics (even in the middle of a transaction), or the characteristics for its next transaction (prior to the start of that transaction). To set the global isolation level at server startup, use the  --transaction-isolation= level  option on the command line or in an option file. Values of  level  for this option use dashes rather than spaces, so the permissible values are  READ-UNCOMMITTED ,  READ-COMMITTED ,  REPEATABLE-READ , or SERIALIZABLE . Similarly, to set the global transaction access mode at server startup, use the  --transaction-read- only  option. The default is  OFF  (read/write mode) but the value can be set to  ON  for a mode of read only. For example, to set the isolation level to  REPEATABLE READ  and the access mode to  READ WRITE , use these lines in the  [mysqld]  section of an option file: 2733 [mysqld] transaction-isolation = REPEATABLE-READ transaction-read-only = OFF mysql>  START TRANSACTION; Query OK, 0 rows affected (0.02 sec) mysql>  SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; ERROR 1568 (25001): Transaction characteristics can’t be changed while a transaction is in progress Transaction Characteristic Scope •With the  GLOBAL  keyword: •The statement applies globally for all subsequent sessions. •Existing sessions are unaffected. •With the  SESSION  keyword: •The statement applies to all subsequent transactions performed within the current session. •The statement is permitted within transactions, but does not affect the current ongoing transaction. •If executed between transactions, the statement overrides any preceding statement that sets the next- transaction value of the named characteristics. •Without any  SESSION  or  GLOBAL  keyword: •The statement applies only to the next single transaction performed within the session. •Subsequent transactions revert to using the session value of the named characteristics. •The statement is not permitted within transactions: