Function ExecInitCheck

src/backend/executor/execExpr.c:309–324

* ExecInitCheck: prepare a check constraint for execution by ExecCheck * * This is much like ExecInitQual/ExecQual, except that a null result from * the conjunction is treated as TRUE. This behavior is appropriate for * evaluating CHECK constraints, since SQL specifies that NULL constraint * conditions are not failures. * * Note that like ExecInitQual, this expects input in implicit-AND fo

 * can just apply ExecInitExpr to produce suitable input for ExecCheck.
 */
ExprState *
ExecInitCheck(List *qual, PlanState *parent)
{
	/* short-circuit (here and in ExecCheck) for empty restriction list */
	if (qual == NIL)
		return NULL;

	Assert(IsA(qual, List));

	/*
	 * Just convert the implicit-AND list to an explicit AND (if there's more
	 * than one entry), and compile normally.  Unlike ExecQual, we can't
	 * short-circuit on NULL results, so the regular AND behavior is needed.
	 */
	return ExecInitExpr(make_ands_explicit(qual), parent);
}

/*
 * Call ExecInitExpr() on a list of expressions, return a list of ExprStates.