Function act_alter_table

src/gpre/sql.cpp:1353–1458

//

static act* act_alter_table()
{
	// create request block

	gpre_req* request = MSC_request(REQ_ddl);

	// get table name and create relation block

	gpre_rel* relation = par_relation(request);

	// CHECK Constraints require the context to be set to the
	// current relation

	gpre_ctx* context = MSC_context(request);
	request->req_contexts = context;
	context->ctx_relation = relation;

	// Reserve context 1 for relation on which constraint is
	// being defined

	context->ctx_internal++;
	request->req_internal++;

	// create action block

	act* action = MSC_action(request, ACT_alter_table);
	action->act_whenever = gen_whenever();
	action->act_object = (ref*) relation;

	// parse action list and create corresponding field blocks

	gpre_fld** ptr = &relation->rel_fields;
	cnstrt** cnstrt_ptr = &relation->rel_constraints;
	cnstrt* cnstrt_str;
	gpre_fld* field;

	while (!end_of_command())
	{
		if (MSC_match(KW_ADD))
		{
			switch (gpreGlob.token_global.tok_keyword)
			{
			case KW_CONSTRAINT:
			case KW_PRIMARY:
			case KW_UNIQUE:
			case KW_FOREIGN:
			case KW_CHECK:
				cnstrt_str = par_table_constraint(request);
				*cnstrt_ptr = cnstrt_str;
				cnstrt_ptr = &cnstrt_str->cnstrt_next;
				break;

			default:
				field = par_field(request, relation);
				*ptr = field;
				ptr = &field->fld_next;
			}
		}