Re: Multiple inserts with two levels of foreign keys

Frame challenge: why can't you just "\copy to" the dev database tables in
the correct order, to satisfy foreign key requirements?

On 10/4/23 18:59, Dow Drake wrote:
> Hi,
>
> I'm trying to write a postgresql script to replicate a hierarchical
> structure in a live database into my development database, where I can
> debug and test more easily.  I can extract the data from the live database
> that needs to be inserted, but I'm having trouble writing the insertion script
>
> Here's a simplified version of the problem I'm trying to solve:
> There are three tables: farms, crops and deliveries where a farm has many
> crops and a crop has many deliveries.
>
> create table farms (
>    id bigint NOT NULL GENERATED BY DEFAULT AS IDENTITY,
>    name character varying(30)
> );
> create table crops (
>    id bigint NOT NULL GENERATED BY DEFAULT AS IDENTITY,
>    farm_id bigint not null
>    name character varying(30)
> );
> create table deliveries (
>    id bigint NOT NULL GENERATED BY DEFAULT AS IDENTITY,
>    crop_id bigint not null
>    ticket character varying(30)
> );
> I want to insert a farm record, then insert two crops associated with that
> farm, then insert two deliveries for each of the the two crops so that in
> the end, my tables look like this:
> farms
> id     name
> 1      'Happy Valley Farm'
>
> crops
> id     farm_id name
> 1        1 'corn'
> 2        1 'wheat'
>
> delvieries
> id       crop_id ticket
> 1 1          '3124'
> 2 2          '3127'
> 3 1          '3133'
> 4 2          '3140'
>
> It's important that the deliveries get assigned to the right crops.  I
> think this post: https://dba.stackexchange.com/questions/199916
> gets close to what I need, but I haven't been able to figure out how to
> adapt it to multiple records.
>
> Thanks for any help on this!
>
>

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Born in Arizona, moved to Babylonia.