Top "Unique-constraint" questions

Unique-constraint is an index that sets one or multiple fields to be unique in a data entity

Allow null in unique column

I've created the following table: CREATE TABLE MMCompany ( CompanyUniqueID BIGSERIAL PRIMARY KEY NOT NULL, Name VARCHAR (150) NOT NULL, PhoneNumber VARCHAR(20) …

sql postgresql database-design null unique-constraint
MySQL: making a column unique?

I have a table that is in production. I realize that some of the columns should be unique. Is it …

mysql phpmyadmin unique-constraint
Using unique constraint on Hibernate JPA2

How can I implement my unique constraints on the hibernate POJO's? assuming the database doesn't contain any. I have seen …

java hibernate unique unique-constraint
How can I create a SQL unique constraint based on 2 columns?

I have a Table like this one: |UserId | ContactID | ContactName --------------------------------------- | 12456 | Ax759 | Joe Smith | 12456 | Ax760 | Mary Smith | 12458 | Ax739 | Carl Lewis | 12460 | …

sql-server sql-server-2005 sql-server-2008 constraints unique-constraint
SQL unique varchar case sensitivity question

I'm trying to populate a SQL table with a list of words. The table itself it pretty simple: CREATE TABLE …

mysql sql case-sensitive varchar unique-constraint
IntegrityError duplicate key value violates unique constraint - django/postgres

I'm following up in regards to a question that I asked earlier in which I sought to seek a conversion …

django postgresql duplicates unique-constraint database-integrity
A Queue that ensure uniqueness of the elements?

I'm looking for a implementation of java.util.Queue or something in the Google collection who behave like a Queue, …

java collections queue guava unique-constraint
Postgresql: Conditionally unique constraint

I'd like to add a constraint which enforces uniqueness on a column only in a portion of a table. ALTER …

postgresql constraints unique-constraint
Add a unique constraint of a sql table as foreign key reference to an another sql table

how to add a unique constraint of a sql table as foreign key reference to an another sql table in …

sql-server unique-constraint
Creating UNIQUE constraint on multiple columns in MySQL Workbench EER diagram

In MySQL Workbench's EER diagram, there is a checkbox to make each column in a table unique, not null, primary …

mysql mysql-workbench unique-constraint multiple-columns workbench