The error code for a unique index violation in SQL is typically "23505" or "23000".

A unique index violation occurs when you try to insert a new row into a table with a unique index, and the values for the indexed columns match the values for an existing row in the table. This can happen if you are trying to insert a duplicate value into a column that has a unique index, or if you are trying to insert a null value into a column that has a unique index and null values are not allowed.

When a unique index violation occurs, the database server will return an error message indicating the violation and the error code. The specific error message and code may vary depending on the database server and client software being used.

For example, in PostgreSQL, the error message for a unique index violation might look like this:


ERROR: duplicate key value violates unique constraint "index_name"
DETAIL: Key (column_name)=(value) already exists.
SQL state: 23505
In MySQL, the error message for a unique index violation might look like this:


ERROR 1062 (23000): Duplicate entry 'value' for key 'index_name   _{Your Comment}