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From:Martijn Tonies Date:March 31 2005 8:24am
Subject:Re: Index on boolean column
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> > >maybe this is a silly question but how useful it is to create indexes
on
> >>columns containing only values 0 and 1 (true and false)?
> >
> > Perhaps, instead of the index, you might revise your schema a bit.
> >
> > Why do you have this boolean column? What are you trying to
> > achieve?
> >
>
>
> I use boolean columns as a flags mostly to mark records as 'exported'. For
> example I have table 'Transactions' and I have to export data for some of
> our customers (never for all of them).

Right. Flags. IMO, flags are bad.

And, as you noticed, it will slow down any queries because a flag cannot
be indexed properly.

Instead, why create a table
Transactions_Exported
TransactionID <primary key>

This can be indexed and will be fast if you want to get info about
any exported transactions.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server
Upscene Productions
http://www.upscene.com

Thread
Index on boolean columnDušan Pavlica30 Mar
  • Re: Index on boolean columnAlec.Cawley30 Mar
  • Re: Index on boolean columnMartijn Tonies30 Mar
  • Re: Index on boolean columnbeacker30 Mar
  • Re: Index on boolean columnDušan Pavlica31 Mar
  • Re: Index on boolean columnMartijn Tonies31 Mar
  • Re: Index on boolean columnMartijn Tonies31 Mar
  • Re: Index on boolean columnDušan Pavlica31 Mar
  • Re: Index on boolean columnMartijn Tonies31 Mar
Re: Index on boolean columnMartijn Tonies31 Mar