Method matchDbKey

src/jrd/optimizer/Retrieval.cpp:2038–2225

//

InversionCandidate* Retrieval::matchDbKey(BoolExprNode* boolean) const
{
	// If this isn't an equality, it isn't even interesting

	const auto cmpNode = nodeAs<ComparativeBoolNode>(boolean);
	const auto listNode = nodeAs<InListBoolNode>(boolean);

	if (cmpNode)
	{
		switch (cmpNode->blrOp)
		{
			case blr_equiv:
			case blr_eql:
			case blr_gtr:
			case blr_geq:
			case blr_lss:
			case blr_leq:
			case blr_between:
				break;

			default:
				return nullptr;
		}
	}
	else if (!listNode)
		return nullptr;

	// Find the side of the equality that is potentially a dbkey.
	// If neither, make the obvious deduction.

	SLONG n = 0;
	int dbkeyArg = 1;
	ValueExprNode* dbkey = nullptr;

	if (cmpNode)
	{
		dbkey = findDbKey(cmpNode->arg1, &n);

		if (!dbkey)
		{
			n = 0;
			dbkeyArg = 2;
			dbkey = findDbKey(cmpNode->arg2, &n);
		}

		if (!dbkey && (cmpNode->blrOp == blr_between))
		{
			n = 0;
			dbkeyArg = 3;
			dbkey = findDbKey(cmpNode->arg3, &n);
		}
	}
	else
	{
		fb_assert(listNode);
		dbkey = findDbKey(listNode->arg, &n);
	}