Question
In such a situation, after creating a table and inserting data, the id has reached 5, for example. If you delete all 5 rows, the next id will be 6. Is it possible to make it start from 1? Reset the id counter.
Answer
id are unique and sequential, but they can have GAPS! This is because id is reserved at the start of a transaction, and if it is restarted, for example, during concurrent access, the id is not rolled back but the next available one is taken.
If you duplicate id, the table will become non-functional due to an SQL error.
How to reset the last id:
Connect to the database:
sudo -u postgres psql -d totum
Set a new last number:
Replace SCHEMA_NAME, NUMBER_HERE, and NAME_TABLE with your values;
SELECT setval('SCHEMA_NAME.NAME_TABLE_id_seq', NUMBER_HERE);
You cannot set it to 0, the minimum value is 1. So if you want to reset the rows, the first row in this case will have id = 2.
Exit:
\q