Re: Newbie table definition question

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Ken Tozier
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Re: Newbie table definition question
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8673E958-1FF4-11D9-A78B-003065F300E2@comcast.net
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Newbie table definition question Ken Tozier <kentozier@comcast.net>
Re: Newbie table definition question Steven Klassen <sklassen@commandprompt.com>
Re: Newbie table definition question Steven Klassen <sklassen@commandprompt.com>
Re: Newbie table definition question Ken Tozier <kentozier@comcast.net>
Re: Newbie table definition question Steven Klassen <sklassen@commandprompt.com>
Re: Newbie table definition question Steven Klassen <sklassen@commandprompt.com>
Re: Newbie table definition question Ken Tozier <kentozier@comcast.net>
Re: Newbie table definition question Ken Tozier <kentozier@comcast.net>
Re: Newbie table definition question Steven Klassen <sklassen@commandprompt.com>
> You can track whatever information you need about the particular trip,
> add rows to the cart associating the trip with the items being
> purchased, and finally the grocery types and items.
>
> CREATE TABLE trips (
>     id bigserial primary key NOT NULL,
>     created timestamp default now() NOT NULL
> );
>
> CREATE TABLE cart (
>     id bigserial primary key NOT NULL,
>     trips_id bigint NOT NULL,
>     grocery_items_id bigint NOT NULL,
        quantity int NOT NULL
> );
>
> CREATE TABLE grocery_types (
>     id bigserial primary key NOT NULL,
>     name text NOT NULL
> );
>
> CREATE TABLE grocery_items (
>     id bigserial primary key NOT NULL,
>     grocery_types_id bigint NOT NULL,
>     name text NOT NULL,
>     price numeric(10,2) NOT NULL,
> );
>
>

So, assuming there's no "quantity" field  defined in the "cart" table, 
if 3 apples, 2 oranges and 1 head of lettuce were purchased on a 
specific shopping trip, I would do something like this?

INSERT INTO cart (trips_id, grocery_items_id) VALUES ({1, 1}, {1, 1}, 
{1, 1}, {1, 2}, {1, 2}, {1, 4})

With a "quantity" field the same shopping trip would look like this:

INSERT INTO cart (trips_id, grocery_items_id, quantity) VALUES ({1, 1, 
3}, {1, 2, 2}, {1, 4, 1})

Having to remember ids for grocery items seem rather user-unfriendly. 
Would this be a candidate for a view? Allowing the user to enter 
something like {{"apples", 3}, {"oranges", 2}, {"lettuce", 1}}

Ken

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