i have 600 records in my postgres database, now when i inserted from django it's generating primary duplication error
Run
python manage.py sqlsequencereset [app_name]
and execute all or just one for the required table SQL statements in the database to reset sequences.

Explanation:
You probably inserted with primary keys already present in it, not letting postgresql to auto-generate ids. This is ok.
This means, internal Postgresql sequence used to get next available id has old value. You need to rest with sequence to start with maximum id present in the table.
Django manage.py has command intended just for that - print sql one can execute in db to reset sequences.
I have inserted data into table from postgresql directly. Now when I try to insert data from django application, it's generating primary key duplication error. How can I resolve this issue?