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RestoreSavePoint
Undo transaction operations back to a savepoint.
Short Name
TRANRST()
Type
Low-Level data file function
Declaration
COUNT RestoreSavePoint(COUNT savpnt)
Description
RestoreSavePoint() rolls the current transaction back to a previously defined savepoint created with a call to SetSavePoint(). savpnt is the savepoint to roll back to, and is the value returned by the call to SetSavePoint(). This allows you to back up in a transaction to a particular point, without having to Abort() or Commit() the entire transaction. For a complete discussion of this process please see Data Integrity in the c-tree Programmer’s Reference Guide.
savpnt can also be specified as a small negative number. -1 means go back to the most current savepoint. -2 means go back one more, etc.
RestoreSavePoint() also clears errors that have occurred since the savepoint.
Return
Value |
Symbolic Constant |
Explanation |
|---|---|---|
0 |
NO_ERROR |
No error occurred. |
71 |
TNON_ERR |
There is no active transaction pending. |
See c-tree Error Codes for a complete listing of valid c-tree error values.
Example
COUNT savepoint;
void domaster() {
Begin( ctENABLE | ctTRNLOG ); /* start transaction with locks */
while( another() ); { /* get next record to add */
savepoint = SetSavePoint();
/* get save point at beginning of each master record */
if ( add_master() < 0 )
Abort(); /* RestoreSavePoint if can't add master rec */
dodetail(); /* process detail records */
}
if ( Commit(ctFREE) )
printf("\nError %d in transaction",uerr_cod);
return;
}
void dodetail() {
while( moredetail() ); { /*get next detail record to add */
if ( add_detail()<0 ) { /* add details, if possible */
RestoreSavePoint( savepoint ) /* with error, return to savept */
return;
}
}
}
See also
Abort(), AbortXtd(), Begin(), ClearSavePoint(), Commit(), SetSavePoint(), TRANRDY()
