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savepoint (7)
  • >> savepoint (7) ( Linux man: Макропакеты и соглашения )
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    NAME

    SAVEPOINT - define a new savepoint within the current transaction
    

     

    SYNOPSIS

    SAVEPOINT savepoint_name
    
    
     

    DESCRIPTION

    SAVEPOINT establishes a new savepoint within the current transaction.

    A savepoint is a special mark inside a transaction that allows all commands that are executed after it was established to be rolled back, restoring the transaction state to what it was at the time of the savepoint.  

    PARAMETERS

    savepoint_name
    The name to give to the new savepoint.
     

    NOTES

    Use ROLLBACK TO SAVEPOINT [rollback_to_savepoint(7)] to rollback to a savepoint. Use RELEASE SAVEPOINT [release_savepoint(7)] to destroy a savepoint, keeping the effects of commands executed after it was established.

    Savepoints can only be established when inside a transaction block. There can be multiple savepoints defined within a transaction.  

    EXAMPLES

    To establish a savepoint and later undo the effects of all commands executed after it was established:

    BEGIN;
        INSERT INTO table1 VALUES (1);
        SAVEPOINT my_savepoint;
        INSERT INTO table1 VALUES (2);
        ROLLBACK TO SAVEPOINT my_savepoint;
        INSERT INTO table1 VALUES (3);
    COMMIT;
    
    
    The above transaction will insert the values 1 and 3, but not 2.

    To establish and later destroy a savepoint:

    BEGIN;
        INSERT INTO table1 VALUES (3);
        SAVEPOINT my_savepoint;
        INSERT INTO table1 VALUES (4);
        RELEASE SAVEPOINT my_savepoint;
    COMMIT;
    
    
    The above transaction will insert both 3 and 4.  

    COMPATIBILITY

    SQL requires a savepoint to be destroyed automatically when another savepoint with the same name is established. In PostgreSQL, the old savepoint is kept, though only the more recent one will be used when rolling back or releasing. (Releasing the newer savepoint will cause the older one to again become accessible to ROLLBACK TO SAVEPOINT and RELEASE SAVEPOINT.) Otherwise, SAVEPOINT is fully SQL conforming.  

    SEE ALSO

    BEGIN [begin(7)], COMMIT [commit(l)], RELEASE SAVEPOINT [release_savepoint(l)], ROLLBACK [rollback(l)], ROLLBACK TO SAVEPOINT [rollback_to_savepoint(l)]


     

    Index

    NAME
    SYNOPSIS
    DESCRIPTION
    PARAMETERS
    NOTES
    EXAMPLES
    COMPATIBILITY
    SEE ALSO


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