New posts in Unique Key

How can I catch UniqueKey Violation exceptions with EF6 and SQL Server?

MySql - Is primary key unique by default?

Unique Key constraints for multiple columns in Entity Framework

How add unique key to existing table (with non uniques rows)

difference between primary key and unique key

How to remove unique key from mysql table

Oracle unique constraint and unique index

MySQL: ALTER IGNORE TABLE ADD UNIQUE, what will be truncated?

Find or insert based on unique key with Hibernate

INSERT ... ON DUPLICATE KEY (do nothing)