Thanks Michael und Adrian for your answers.
I think that " My guess is that the SERIAL was defined for the column, then the data was added with id values, but the counter for the sequence behind the SERIAL was not updated to a value greater the the last id added. " is a correct description of what happens. For avoiding the need of an additional command for updating the sequence before every insert statement: Is there a way to specify the desired behaviour (that PG always provides conflict-free id values, eg. max(id)+1 when id values are not given explicitly in the INSERT statement) already whend defining(!) the table in the CREATE TABLE statement ? Original Message processed by david® Re: Problem with SqlState=23505 when inserting rows 15. Januar 2020, 17:51 Uhr Von Michael Lewis An Werner Kuhnle Cc PostgreSQL General On Wed, Jan 15, 2020 at 9:41 AM Werner Kuhnle <w...@kuhnle.com> wrote: I've tried to using the newer definition: id int GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY but that does not solve the problem. Is there a way to define id columns to that when the database provides values, it recognizes already existing values avoiding conflicts. You'll need to run something like the below to set the next value to the max current value. You'll just have to figure out the name of the sequence that is automatically created whether you use the pseudo type serial, or the newer IDENTITY option. Both are implemented with a sequence. --set sequence to max ID on a table select setval( 'table_name_id_seq', ( select max(id) + 1 from table_name ) );
