Function act_update

src/gpre/sql.cpp:4510–4820

//

static act* act_update()
{
	if (MSC_match(KW_OR) && MSC_match(KW_INSERT))
		return act_upsert();

	const TEXT* transaction = NULL;

	par_options(&transaction);

	// First comes the relation.  Unfortunately, there is no way to identify
	// its database until the cursor is known.  Sigh.  Save the token.

	SCHAR r_name[NAME_SIZE], db_name[NAME_SIZE], owner_name[NAME_SIZE];
	SQL_relation_name(r_name, db_name, owner_name);

	// Parse the optional alias (context variable)

	gpre_sym* alias = gpreGlob.token_global.tok_symbol ? NULL : PAR_symbol(SYM_dummy);

	// Now we need the SET list list.  Do this thru a linked list stack

	if (!MSC_match(KW_SET))
		CPR_s_error("SET");

	gpre_req* request = MSC_request(REQ_mass_update);
	gpre_rel* relation = SQL_relation(request, r_name, db_name, owner_name, true);
	gpre_ctx* input_context = MSC_context(request);
	input_context->ctx_relation = relation;

	if (alias)
	{
		alias->sym_type = SYM_context;
		alias->sym_object = input_context;
		HSH_insert(alias);
		gpreGlob.token_global.tok_symbol = HSH_lookup(gpreGlob.token_global.tok_string);
	}

	gpre_lls* stack = NULL;
	SSHORT count = 0;

	do {
		gpre_nod* set_item = MSC_node(nod_assignment, 2);
		set_item->nod_arg[1] = SQE_field(NULL, false);
		if (!MSC_match(KW_EQUALS))
			CPR_s_error("assignment operator");
		set_item->nod_arg[0] = SQE_value_or_null(request, false, NULL, NULL);
		MSC_push(set_item, &stack);
		count++;
	} while (MSC_match(KW_COMMA));

	gpre_nod* set_list = MSC_node(nod_list, count);
	gpre_nod** const end_list = set_list->nod_arg + count;
	gpre_nod** ptr = end_list;

	while (stack)
		*--ptr = (gpre_nod*) MSC_pop(&stack);

	// Now the moment of truth.  If the next few tokens are WHERE CURRENT OF