Function ExecCheck

src/backend/executor/execExpr.c:864–883

* ExecCheck - evaluate a check constraint * * For check constraints, a null result is taken as TRUE, ie the constraint * passes. * * The check constraint may have been prepared with ExecInitCheck * (possibly via ExecPrepareCheck) if the caller had it in implicit-AND * format, but a regular boolean expression prepared with ExecInitExpr or * ExecPrepareExpr works too. */

 * ExecPrepareExpr works too.
 */
bool
ExecCheck(ExprState *state, ExprContext *econtext)
{
	Datum		ret;
	bool		isnull;

	/* short-circuit (here and in ExecInitCheck) for empty restriction list */
	if (state == NULL)
		return true;

	/* verify that expression was not compiled using ExecInitQual */
	Assert(!(state->flags & EEO_FLAG_IS_QUAL));

	ret = ExecEvalExprSwitchContext(state, econtext, &isnull);

	if (isnull)
		return true;

	return DatumGetBool(ret);
}

/*
 * Prepare a compiled expression for execution.  This has to be called for