Method dsqlPassAliasList

src/jrd/RecordSourceNodes.cpp:418–521

The passed alias list fully specifies a relation. The first alias represents a relation specified in the from list at this scope levels. Subsequent contexts, if there are any, represent base relations in a view stack. They are used to fully specify a base relation of a view. The aliases used in the view stack are those used in the view definition.

// represent base relations in a view stack. They are used to fully specify a base relation of
// a view. The aliases used in the view stack are those used in the view definition.
dsql_ctx* PlanNode::dsqlPassAliasList(DsqlCompilerScratch* dsqlScratch)
{
	DEV_BLKCHK(dsqlScratch, dsql_type_req);

	ObjectsArray<MetaName>::iterator arg = dsqlNames->begin();
	ObjectsArray<MetaName>::iterator end = dsqlNames->end();

	// Loop through every alias and find the context for that alias.
	// All aliases should have a corresponding context.
	int aliasCount = dsqlNames->getCount();
	USHORT savedScopeLevel = dsqlScratch->scopeLevel;
	dsql_ctx* context = NULL;
	while (aliasCount > 0)
	{
		if (context)
		{
			if (context->ctx_rse && !context->ctx_relation && !context->ctx_procedure)
			{
				// Derived table
				dsqlScratch->scopeLevel++;
				context = dsqlPassAlias(dsqlScratch, context->ctx_childs_derived_table, *arg);
			}
			else if (context->ctx_relation)
			{
				// This must be a VIEW
				ObjectsArray<MetaName>::iterator startArg = arg;
				dsql_rel* viewRelation = context->ctx_relation;

				dsql_rel* relation = nullptr;
				dsql_prc* procedure = nullptr;

				// find the base table using the specified alias list, skipping the first one
				// since we already matched it to the context.
				for (; arg != end; ++arg)
				{
					if (!METD_get_view_relation(dsqlScratch->getTransaction(),
						dsqlScratch, viewRelation->rel_name, *arg,
						relation, procedure))
					{
						break;
					};

					--aliasCount;

					if (!relation)
						break;
				}

				// Found base relation
				if (aliasCount == 0 && (relation || procedure))
				{
					// AB: Pretty ugly huh?
					// make up a dummy context to hold the resultant relation.
					dsql_ctx* newContext = FB_NEW_POOL(dsqlScratch->getPool()) dsql_ctx(dsqlScratch->getPool());
					newContext->ctx_context = context->ctx_context;
					newContext->ctx_relation = relation;
					newContext->ctx_procedure = procedure;