From: Joerg Bruehe
Date: February 15 2011 6:58pm
Subject: Re: Insert only if the entry doesn't exist
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Hi!


Andre Polykanine wrote:
> Hello Rolando,
>=20
> So if I do
> "INSERT IGNORE INTO `Votes` SET `EntryId`=3D'12345', UserId`=3D'789'";
> it  *won't* insert the second row if there's a row with EntryId set to
> 12345 and UserId set to 789?

If you want to have at most one vote per user on any entry, IMO you
should have a "unique index" on that combination of fields.


Aside:
Assuming you "*Id" values are numeric types, you should stop using
quotes around them: quotes enclose strings.
I know MySQL implicitly converts numbers to strings and vice versa, but
this costs performance and IMO is a bad idea anyways.
I feel a programmer should know the distinction of numeric and string
types and keep them separate in a well-structured application.


HTH,
J=F6rg

--=20
Joerg Bruehe,  MySQL Build Team,  joerg.bruehe@stripped
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