[CM][BUG]When inherit tables, inherit their PK is error.

1 Create table1：
CREATE TABLE "a1"(
"id" integer,
"name" character(5),
CONSTRAINT pk_a1_id PRIMARY KEY("id")
);
2 Create table2:
CREATE TABLE "b1"(
"sid" integer,
"sna" national character(2),
CONSTRAINT pk_b1_sid PRIMARY KEY("sid")
);
3 Create table3:
CREATE TABLE "c1"
UNDER "a1","b1"(
"c1" character(3)
);

Actual result:
In table c1, we will see two PK. It's error.

Addtional
If it is permitted has more than one PK. Cann't set c1 column to PK.
According sql regular, one table cannont has more than one PK.