Re: exposing the primary key?
Re: exposing the primary key?
- Subject: Re: exposing the primary key?
- From: Musall Maik <email@hidden>
- Date: Sat, 01 Mar 2014 10:29:06 +0100
Am 28.02.2014 um 22:25 schrieb Theodore Petrosky <email@hidden>:
> I need to create an Entity that will have a user visible id number. I thought I would just use the primaryKey but I recall reading so many times don't use the primaryKey for this.
>
> This is a very simple Entity. It has a description, a Client, and a boolean (isActive). When the user views a list of these Entities, he/she will see:
>
> id number description client
> 3456 Blue Dress Amex
>
> when I insert a new Entity, I only need to supply the description and Client (from a popup). WO will supply the ID number. So why not use the primaryKey here? The user can never edit it. and none of these Entities will ever be deleted.
Here are some more reasons.
Assuming you want the id number to stay constant, you’re giving up any chance of later reorganizing your table structure, which often involves rewriting tables with new primary keys.
And by making the id number separate, you can employ your own schemes on that. You could make it alphanumeric, like „H23M“, which has a far larger value space with fewer digits to remember for people, if they’re supposed to memorize it. (Primary keys could be like that, too, but then you can’t just draw that from a sequence.) You could even decide to change the scheme later on, without assigning new numbers to every old record, just by changing the algorithm that creates those ids.
Nevertheless you should create a unique index on the id number as an additional safety net to get a db exception if your application code fails to ensure uniqueness.
Maik
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