Why is the limit not working?

Question

PostgreSQL

you need to set a limit on the field so that it can take only those values ​​\u200b\u200bthat would begin with a Russian letter
, so I create

ALTER TABLE abonents
ADD CONSTRAINT last_name_check
CHECK (last_name LIKE '[А-я]%') NOT VALID;

I see that everything is attached,

but nothing works, does not allow me to insert any lines

Answer 1

They wrote that last_name should start with the string [А-з] - this is how it is checked.

melkij=> select '[A]ds' like '[A]%';
?column?
----------
t
(1 line)

Where do you need a query rewrite system if you do not distinguish regular expressions from like?
Why not valid is better I won’t even ask.

Answer 2

Colleagues, the person simply confused the syntax for SIMILAR TO expressions and for LIKE expressions.
correct syntax

ALTER TABLE abonents
ADD CONSTRAINT last_name_check
CHECK (last_name SIMILAR TO '[А-я]%');

Although I am an adherent of the usual regexp and would write like this.

ALTER TABLE abonents
ADD CONSTRAINT last_name_check
CHECK (last_name ~ '[А-я].*');