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What does duplicate key violate the unique constraint?
ERROR: duplicate key violates unique constraint That likely means that the primary key sequence in the table you’re working with has somehow become out of sync, likely because of a mass import process (or something along those lines).
What happens when an insert violates the unique constraint?
That attempted insert violated the unique constraint of the primary key. That violation threw an exception. That exception caused the transaction and the initial commit to rollback. Transactions, even AFTER INSERT that throw exceptions cause the insert to rollback. Thanks for contributing an answer to Database Administrators Stack Exchange!
Do you need a duplicate key in PostgreSQL?
Now a new entry had to be inserted manually via SQL. After that the sequence was out of sync and no more records could be inserted via the app. As mentioned in the answer from @adamo, the sequence must be synchronized manually. For this purpose the name of the sequence is needed.
Is it necessary to add a unique constraint to PostgreSQL?
Adding another unique constraint isn’t necessary to do that. The “duplicate key” error is telling you that the work was not done because it would produce a duplicate key, not that it discovered a duplicate key already commited to the table. From http://www.postgresql.org/docs/current/interactive/datatype.html.
Is the duplicate key in NY stations serial?
The id field in your ny_stations table does not seem to be defined as a serial, so it is expected that pg_get_serial_sequence will return nothing. The duplicate you get relates to one of the records in your SELECT DISTINCT
How is the uniqueness constraint created in Java?
Each worker thread processes a packet (a “report”), checks if it is valid (where each report must have a unique unit_id, time, latitude and longitude), grabs a db connection from the connection pool, and then inserts the report into the reports table. The uniqueness constraint is created with postgresql and dubbed “reports_uniqueness_index”.
What happens if you violate the constraint in Java?
If an attempt is made to insert a record that violates the constraint, no exception is thrown or logged, and if executed inside a transaction, the transaction is not affected. The function returns a value which you can use to see if the record was inserted or not. It is a very basic example, but should illustrate the point.
When is serial implied unique in PostgreSQL 7.3?
Note: Prior to PostgreSQL 7.3, serial implied UNIQUE. This is no longer automatic. If you wish a serial column to be in a unique constraint or a primary key, it must now be specified, same as with any other data type. Referrence – https://www.calazan.com/how-to-reset-the-primary-key-sequence-in-postgresql-with-django/