Method of executing before-triggers in an active database

摘要

A method for executing before-triggers in an active database. A tree of actions is constructed for each activated before-rigger and a tree of operators is constructed for the statement that activates the trigger. A table affecting operator that is included in the activating statement is removed from the statement tree and a temporary execution operator is formed from any remaining actions of the activating statement. The temporary execution operator and the activated before-triggers are then included in an insertion operator that is configured to send updated rows into a temporary table. The table affecting operator is then interconnected to execute subsequent to the insertion operator. Any activated row-after and statement-after triggers are interconnected to execute subsequent to the execution of the table-affecting operator.