Re: gEDA-user: database driven component chooser - part II

[Christoph Lechner <cl0023@xxxxxxx>]

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Levente wrote:
> Christoph Lechner <cl0023@xxxxxxx> wrote:
>> OK. I took a look at the database. So a question came to mind when I saw
>> the layout of the 'device' table:
>> Why do you store the relationship between entries in the 'device' table
>> and entries in the 'supplier' table in fields named supplier*,
>> ordering_code*, price* in the 'device' table? What if there are more
>> than 3 suppliers for any given part?
>>
>> As the relation between 'device' and 'supplier' is a many-many
>> relationship, you'd be better off creating just another table, holding
>> the device's ID, the ID of the supplier and fields for the ordering_code
>> and the price. Then you only need to LEFT JOIN the tables
>> rel-device-supplier and supplier and you get all suppliers for a given
>> part. This would give you a somewhat tidier DB layout ...
> 
> Ok,
> 
> I have modified the structure of my database. Thank's for the hint.
Ok, seen that. Looks really nice now.

But make sure to add an ID field with autoincrement turned on to the new
relation table 'source' to avoid collisions. These can really screw it up :(

Why not add an index over 'dev_ID' and 'sup_ID'? Would tweak the
performance quite alot.

Just another 2 cents :)

CU
- - cl
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