Is it possible to set a unique field in two tables?

Question

MySQL

Good afternoon!
There are 2 tables:

1. table1
   
   • param1_1
     
   • param1_2
     
   
   
2. table2
   
   • param2_1
     
   • param2_2
     
   
   

It is necessary to make sure that param1_1 and param2_1 are unique.
Is it possible to arrange this without checking 2 tables each time?

Answer 1

Slightly strange structure.
If they must be unique, then make one of the columns a FOREIGN KEY and make both columns UNIQUE.
Or make such a structure so that both columns are in the same table and make the index UNIQUE composite.

Answer 2

If you want a unique key for 2 tables (which is rather strange), then you can simply put a constraint on the primary key. For example like this:

CREATE TABLE `table_1` (
`id` INT CHECK(id BETWEEN 10000 AND 49999)
);
CREATE TABLE `table_2` (
`id` INT CHECK(id BETWEEN 50000 AND 99999)
);

Answer 3

But in PostgreSQL, this is easy to do through sequences. And so everyone is right, it is better to redo the base itself. She is clearly not good.

Answer 4

"External" counter either in one table even in another odd