How to represent a bi-directional list in db?

"prev_stage_id" of table "stages" Is it not possible to create "nullable" self referencing foreign keys? -- Pankaj Jangid

Re: How to represent a bi-directional list in db?

Francisco Olarte writes: > On Sun, Sep 22, 2019 at 4:25 PM Pankaj Jangid wrote: >> CREATE TABLE stages ( >>id SERIAL PRIMARY KEY, >>name VARCHAR(80) NOT NULL, >>created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP, >>upda

Re: How to represent a bi-directional list in db?

in a table. I got the idea. I'll add another column in the processes table which points to the first stage (first_stage_id). And quries Forward pass: 1. select name from stages where id = 2. select name from stages where prev_id = 3. repeat (2) Backward pass: 1. select name from stages where prev_id = 2. select name from stages where id = 3. repeat (2) This is assuming I also create a circular list. I can also store last_stage_id in the process table if we don't want to create circular list in db. Regards. -- Pankaj Jangid

Re: How to represent a bi-directional list in db?

sco. Got the idea. -- Pankaj Jangid

Re: managing primary key conflicts while restoring data to table with existing data

ng pkey 3. remove pkey references and the columns 4. make UUID column the pkey 5. remove old pkey column. -- Pankaj Jangid

A post describing PostgreSQL 12 Generated Columns

Found a very nice article about PostgreSQL 12 Generated Columns. I thought this might be useful for everyone. Hence sharing. https://pgdash.io/blog/postgres-12-generated-columns.html -- Pankaj Jangid

Re: PG11 Parallel Thanks!!

user story. Thanks for sharing your experience, Jason. -- Pankaj Jangid

Re: PG 12 not yet for mac

Tomas Vondra writes: > On Mon, Oct 07, 2019 at 11:11:43AM -0400, Ravi Krishna wrote: >>https://postgresapp.com/downloads.html >> >>The link which says PG 12 is actually PG 11. >> > > Not sure if the link is correct or not (it seems to point to > Postgres-2.3-12.dmg, which seems like it might be v

Using PostgreSQL for Machine Learning Data Pipelines

PostgreSQL is deployed for ML use. Any pointers referring to study material will be helpful. Please share in this thread. -- Thanks & Regards, Pankaj Jangid

Re: Storing a time interval

ypically you need to surround the outer column in brackets - e.g. > (dates).discount_last_date. If you are using an ORM library, does it know > how to deal with that? > I faced a similar issue when using Enums with with rust lang. The Diesel ORM didn't support it directly. Had to stru

Re: How to update a table with the result of deleting rows in another table

On Tue, Oct 06 2020, Hemil Ruparel wrote: > with data as ( > delete from orders > where customer_id = > and date = '2020-10-05' returning price > ), total as ( > select sum(price) from data > ) > update paymentdetail > set temp_credit = temp_credit + (select * from total) > w