Control password attribute with CHECK in SQL Server - sql-server

Question

PD:Some names are in Spanish, sorry.
I have a table containing columns Usuario and Contraseña.
For each one it will be necessary to determine: login user (unique in the system and identification) and access password (which must contain 5 letters and 2 numbers - exact length 7). Consider that the login name must have exactly 10 characters
The table created is as follows:
CREATE TABLE Empleado
(
Usuario varchar(10) NOT NULL UNIQUE
CHECK(LEN([Usuario]) = 10),
Contraseña varchar(7) NOT NULL
CHECK (LEN([Contraseña]) = (7) AND [Contraseña] LIKE '%[0-9]%' AND [Contraseña] LIKE '%[A-Z]%')
)
And the data is inserted like this:
INSERT INTO Empleado (Usuario, Contraseña)
VALUES ('santiago21', 'qwerty1')
INSERT INTO Empleado (Usuario, Contraseña)
VALUES ('FaaacuuUwU', 'qwertY1')
The problem is that the second insert should take it, but the first one should not, which it DOES NOT DO.
Does anyone know how I should do it? Thank you.

Answer 1

We can take advantage of SQL Server's enhanced LIKE operator here:
CREATE TABLE Empleado (
Usuario varchar(10) NOT NULL UNIQUE CHECK(LEN([Usuario]) = 10),
Contraseña varchar(7) NOT NULL CHECK (
LEN([Contraseña]) = 7 AND
[Contraseña] LIKE '%[0-9]%[0-9]%' AND -- 2 numbers
[Contraseña] LIKE '%[A-Za-z]%[A-Za-z]%[A-Za-z]%[A-Za-z]%[A-Za-z]%') -- 5 letters
)
);
Edit:
In general you should not be storing clear text passwords in your database. The reason for this is that should anyone (internal or external) gain access to your Empleado table, they would get access to every credential in your entire system.
Instead, a much safer approach would be to first irreversibly hash every password and then store the hash. Then, in the unlikely event that someone undesirable might gain access to your table, they wouldn't get passwords, just usernames with some gibberish password hashes that they couldn't easily back out to the original passwords.