Is it possible to create a dynamic(with a select) check constraint?

Question

create table a (col_to_be_coded_fora number);
create table b (col_to_be_coded_forb number);
create table c (col_name varchar2(20), col_code number, col_desc varchar2(20));
insert into c values ('col_to_be_coded_fora', 1, 'active');
insert into c values ('col_to_be_coded_fora', 2, 'de-active');
insert into c values ('col_to_be_coded_fora', 3, 'pending');
insert into c values ('col_to_be_coded_forb', 10, 'school');
insert into c values ('col_to_be_coded_forb', 20, 'hospital');
insert into a values ( 1); -- meaning 'active' for table a, column col_to_be_coded_fora, can go in
insert into a values (10); -- meaning nothing for table a, column col_to_be_coded_fora, must give error
insert into b values ( 1); -- meaning nothing for table b, column col_to_be_coded_forb, must give error
insert into b values (10); -- meaning 'school' for table b, column col_to_be_coded_fora, can go in
I know i can handle this problem with dividing table c into to tables and creating foreign key relationship.
in this demo case i have only a and b, 2 tables but i want to encode thousands of tables with a table like c.
İs it possible to create a dynamic check constraint on a table which selects c table for the inputs that have permision?
Or do i have to use after insert, update triggers on table a and b to ensure this functionality?
Is there a smarter implementation for this need, may be a design change?
Thank you,
Kind regards.
Tonguç

Answer 1

Hi Tonguç,
A small design change makes it possible to do this with simple foreign key constraints.
I would do something like:
ual303@ORKDEV01> CREATE TABLE c (
  2    col_name VARCHAR2(20),
  3     col_code NUMBER,
  4     col_desc VARCHAR2(20),
  5     PRIMARY KEY (col_name, col_code)
  6  );
Tabel is aangemaakt.
ual303@ORKDEV01> CREATE TABLE a (
  2    col_to_be_coded_fora NUMBER PRIMARY KEY,
  3     col_name VARCHAR2(20) DEFAULT 'col_to_be_coded_fora' CHECK (col_name = 'col_to_be_coded_fora'),
  4     FOREIGN KEY (col_name, col_to_be_coded_fora) REFERENCES c
  5  );
Tabel is aangemaakt.
ual303@ORKDEV01> CREATE TABLE b (
  2    col_to_be_coded_forb NUMBER PRIMARY KEY,
  3     col_name VARCHAR2(20) DEFAULT 'col_to_be_coded_forb' CHECK (col_name = 'col_to_be_coded_forb'),
  4     FOREIGN KEY (col_name, col_to_be_coded_forb) REFERENCES c
  5  );
Tabel is aangemaakt.
ual303@ORKDEV01> insert into c values ('col_to_be_coded_fora', 1, 'active');
1 rij is aangemaakt.
ual303@ORKDEV01> insert into c values ('col_to_be_coded_fora', 2, 'de-active');
1 rij is aangemaakt.
ual303@ORKDEV01> insert into c values ('col_to_be_coded_fora', 3, 'pending');
1 rij is aangemaakt.
ual303@ORKDEV01> insert into c values ('col_to_be_coded_forb', 10, 'school');
1 rij is aangemaakt.
ual303@ORKDEV01> insert into c values ('col_to_be_coded_forb', 20, 'hospital');
1 rij is aangemaakt.
ual303@ORKDEV01> -- meaning 'active' for table a, column col_to_be_coded_fora, can go in
ual303@ORKDEV01> insert into a(col_to_be_coded_fora) values ( 1);
1 rij is aangemaakt.
ual303@ORKDEV01> -- meaning nothing for table a, column col_to_be_coded_fora, must give error
ual303@ORKDEV01> insert into a(col_to_be_coded_fora) values (10);
insert into a(col_to_be_coded_fora) values (10)
FOUT in regel 1:
.ORA-02291: integrity constraint (UAL303.SYS_C0033537) violated - parent key not found
ual303@ORKDEV01> -- meaning nothing for table b, column col_to_be_coded_forb, must give error
ual303@ORKDEV01> insert into b(col_to_be_coded_forb) values ( 1);
insert into b(col_to_be_coded_forb) values ( 1)
FOUT in regel 1:
.ORA-02291: integrity constraint (UAL303.SYS_C0033540) violated - parent key not found
ual303@ORKDEV01> -- meaning 'school' for table b, column col_to_be_coded_fora, can go in
ual303@ORKDEV01> insert into b(col_to_be_coded_forb) values (10);
1 rij is aangemaakt.
ual303@ORKDEV01>Cheers,
Colin