I have the following schema in PostgreSQL How can I enforce the constraint that studentmarks.marks_scored <= exam.total_marks such that the behaviour is just like the CHECK constraint? Answer Use trigger. You need to create trigger function first. Then create trigger. NOTE I have tested in postgres
Tag: check-constraints
Why can’t I add a column to an existing table with a checkConstraint that references other columns in SQL
I’m using SQL Server and am trying to add a column and a check constraint. I’ve found that the following works: However a less verbose way of writing this does not work: The following error is output: Column CHECK constraint for column ‘isTrue’ references another column, table ‘t…
SQL CHECK() how to check if input is numeric value?
Hey how can I check if the input has 5 numbers? I tried everything like isnumeric/LIKE ‘%[0-9]%’ they all not working… I tried the following but it doesn’t work.. please help Answer You can use GLOB operator: See the demo.
Check digit constraint in SQLite
I’m trying to create a constraint for an id (5 digits in length) where the 5th digit is the last digit of the value (1 x d1 + 3 x d2 + 1 x d3 + 3 x d4). For instance, if the first four characters of the id are 1234, then the fifth digit is the last digit of
Can I allow only certain specific strings to be inputted for a table in Oracle 10G?
In this table, I want a constraint such that, name inputted should be only ‘trial’,’experiment’ or ‘test’. Answer You can add the CHECK constraint as follows: If you don’t want the null values in the name then you can also use NOT NULL constraint on the name column. W…
How to deal with Case Sensitivity in PostgreSQL
I have a master table for color codes which stores various unique color values. It has a column Color_value on which UNIQUE constraint has been applied. However it is accepting both ‘Black’ and ‘black’ values. How can such situations be handled? Answer You can create a unique index lik…
Oracle SQL Developer limit number of character of datatype char(5)
I was tasked to implement a table with a variable groupcode. There are several requirements. char(5) 2 or 4 uppercase letters plus 1 digit whose value is between 1 and 4 (e.g., AA1, AABB1) Any input other violating point 1 and 2 should be banned The only thing I can come up with is regexp_like but my efforts …
non UNIQUE constraints
So, I got in this situation: I create a table (let say model_a), in this table I have 2 cols (let say col1 and col2). I need a constraint that satisfy this reality: It’s not UNIQUE constraint, you can duplicate the first row. The only one time this constraint active is col1 is the same but col2 is diffe…
SQL query to set CHECK constraint on a column based on the value in other column
I need to set a CHECK constraint on a column based on the value in other column (both within the same table) Like when COLUMN A is NULL, COLUMN B should be NULL But if COLUMN A has values 1 or 2 or 3 then COLUMN B should definitely have a date value. Answer Define B as a date. And
Create a table for following condition
condition for the problem to be solved: The code i tried to do is I couldn’t solve the first condition and so i am getting right parenthesis missing for final condition Answer I would translate your requirement as follows: Changes to your original code: you want NUMERIC rather than NUMBER ArCode must be…