Caché ObjectScript Reference - InterSystems Documentation

Caché ObjectScript CommandsArgumentspcAn optional postconditional expression. Caché executes the command if the postconditionalexpression is true (evaluates to a non-zero numeric value). Caché does not execute the commandif the postconditional expression is false (evaluates to zero). For further details, referto Command Postconditional Expressions in Using Caché ObjectScript.ExamplesThe following example shows the effects of TROLLBACK on nested transactions. EachTSTART increments $TLEVEL and sets a global. Issuing a TCOMMIT on the inner nestedtransaction decrements $TLEVEL, but the commitment of changes made in a nested transactionis deferred. In this case, the subsequent TROLLBACK on the outer transaction rollsback all changes made, including those in the inner “committed” nested transaction.SET ^a(1)="[- - -]",^b(1)="[- - -]"WRITE !,"level:",$TLEVEL," ",^a(1)," ",^b(1)TSTARTLOCK +^a(1)SET ^a(1)="hello"WRITE !,"level:",$TLEVEL," ",^a(1)," ",^b(1)TSTARTLOCK +^b(1)SET ^b(1)="world"WRITE !,"level:",$TLEVEL," ",^a(1)," ",^b(1)TCOMMITWRITE !,"After TCOMMIT"WRITE !,"level:",$TLEVEL," ",^a(1)," ",^b(1)TROLLBACKWRITE !,"After TROLLBACK"WRITE !,"level:",$TLEVEL," ",^a(1)," ",^b(1)QUITThe following example shows how TROLLBACK rolls back global variables, but not localvariables:140 Caché ObjectScript Reference