Re: Non-primary auto-incrementing field with Postgres

On Monday 19 June 2017 16:29:48 Thomas Hauk wrote:

> I am working on a project that uses Django 1.10.5 with Postgres 9.6

> (and Python 3.6.1).

>

> I am currently migrating historical data from an old system into the

> new system. This historical data has a table with a (non-primary key)

> "ID" column. I would like to migrate these rows into the new

> database, and have that column be auto-incrementing (starting from,

> say, 100000) for new rows inserted.

>

> I think the way to do this with raw Postgres SQL would be to create a

> serial field, and then run a SQL command like "SELECT

> SETVAL('some_table_field_id_seq', 100000)". I think. :)

>

> Does Django expose functionality that lets me accomplish this?

 

First and foremost, verify if ID meets your requirements:

- All values are unique

- They are integers

- Their values are smaller then your new cut-off (100000)

 

Then you can simply transform the field explicitly to primary key and then to BigAutoField. Setting the next value can be done using RunSQL.

 

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Melvyn Sopacua