I have below two table for which when i query table TEST_RUA: select CLASS, ID_LL, ID_UU, TKR from TEST_RUA where ID_UU= ‘GV9999B12M0’ it returns: CLASS ID_LL ID_UU TKR Bond (null)…
Tag: unique-constraint
How do I make sure that all rows with the same foreign key have unique names in my PostgreSQL database?
I have a PostgreSQL database with two tables: Team and Project, in a one-to-many relationship. Team has these columns: id name Project has these: id name team_id I’d like to make sure that the projects within a team must have unique names. Projects belonging to different teams should be able to share names without a problem, so UNIQUE doesn’t really
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 like this: That said, it would be much simpler to make your
Are SQL Server unique constraints “Silent” or do they raise an exception?
I want to prevent inserting duplicate values into my tables. At first, I added code to check if the value already existed in the database, but that seems like a lot of overhead / wasted time if I can prevent it at the DDL level. So I found this and changed one of my tables (as an example) from this:
PostgreSQL. constraint allowing only one of many possible values
I have statuses like this: started,calculated,finished I need a constraint allowing only one NOT finished status in a table. This is allowed: this is forbidden due to two not finished statuses: Answer You can use a filtering unique index: The trick is to pass a fixed value instead of a column name to the on clause of the index (we
How to avoid MySQL composite primary key permutations?
CREATE TABLE Friends_Relations( buddy_id VARCHAR(255) NOT NULL, mate_id VARCHAR(255) NOT NULL, PRIMARY KEY (buddy_id, mate_id), FOREIGN KEY (buddy_id) REFERENCES Users(id) ON DELETE …
Check Constraint with Filtering Logic
I have a table that has bit column called “Flag” it does not allow NULL. A requirement here is to ALWAYS have Flag=1 set for every Id in the table below but only 1 time per each unique Id and Flag columns combination. At the same time all other rows can be have Flag=0 set multiple times if there are
SQL – Violation of UNIQUE KEY constraint
I am trying to find the solution for the below query: There are declared tables @Country and @WHO (World Health Organization). Insert all possibles countries from table @Country into table @WHO. …
Unique value Constraint with multiple columns across the table, not the combination in Oracle
In oracle is there a way to enforce uniqueness among two columns? Its not the uniqueness among combination of two columns, but values across table among two columns. References: Unique value constraint across multiple columns Example data, which should not be allowed: Unique constraint on combination of two columns? My Oracle Version: Answer I would use a check() constraint to
Check constraint before insert a value into the database
I’m trying to create a table to store order_details. The table has a column status that should only be allowed to contain the value true once per each order_id, but may contain the value false multiple times per order_id. I want to do this within the table structure itself. Any help would be appreciated. Thanks in advance. Answer You can