Preventing unique key constraint violation when pre-existing row has 'expired'
44786
Primary key for link/junction table with time-dependent data
105896
Finding a Primary Key Constraint on the fly in SQL Server 2005
58229
Is a table without a primary key normalized?
158559
Why does Postgres generate an already used PK value?
91860
Error 1022 - Can't write; duplicate key in table
16324
How does a PreparedStatement avoid or prevent SQL injection?
105889
PostgreSQL multi-column unique constraint and NULL values
21193
Prevent restoring row if error was rised while editing
2141
how do I insert a default row?
28589
How can I prevent gaps in a MySQL table AUTO_INCREMENT field?
145311
Generate an increment ID that is unique for a given value of a foreign key
121322
How do you drop a default value or similar constraint in T-SQL?
68103
Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints
17103
Making unique key case insensitive
144902
Unique keys in Entity Framework 4
32901
Adding a constraint to prevent duplicates in SQL Update Trigger
34058
How to debug the mysterious "duplicate value found:  duplicates value on record with id: " error