Java Programming with Oracle SQLJ

9.3. The SET TRANSACTION Statement

The SET TRANSACTION statement may be used to explicitly begin a transaction. Using it, you can change the transaction isolation level from its default.

If the SET TRANSACTION statement is used, it must be the first statement in the transaction.

The syntax for a SQLJ executable statement containing the SET TRANSACTION statement is:

#sql {
  SET TRANSACTION [
access_mode],
  [ISOLATION LEVEL 
transaction_isolation_level]
};

The syntax elements are as follows:

access_mode

Specifies the access mode for the transaction, which indicates whether the transaction can only read data or can both read and write data. The access mode may be set to one of the following values:

READ ONLY

READ ONLY means that the transaction may contain only SELECT statements, and that the DML statements INSERT, UPDATE, DELETE, and SELECT FOR UPDATE are not allowed. The Oracle JDBC drivers do not support READ ONLY.

READ WRITE

This is the default access mode. READ WRITE means that all DML statements are allowed in the transaction.

transaction_isolation_level

Specifies the transaction isolation level to use for the transaction. The following values are valid:

SERIALIZABLE

Prohibits dirty reads, non-repeatable reads, and phantom reads.

READ COMMITTED

Prohibits dirty reads. Allows non-repeatable reads and phantom reads.

The following statement sets the transaction ...