If you have 1000 records with 'No' and 10000000 records with 'Yes', then an index on the Boolean field could make searches for records = 'No' considerably quicker (though it depends on other indexed fields in the query as well), but searches for records = 'Yes' a bit slower.

HTH,
Set

-----Original Message-----
From: firebird-support@yahoogroups.com [mailto:firebird-support@yahoogroups.com] On Behalf Of Marius Labuschagne
Sent: 15. januar 2010 06:50
To: firebird-support@yahoogroups.com
Subject: [firebird-support] To Index or not to Index

Hello,

Can someone please tell me if I should build an index on a field when
the the values for the field is always a boolean value (Yes or No).

I execute a lot of queries against this table based on whether the field
is 'No'. Everyday approximately 1000 new rows of data gets stored into
this table where the field will be 'No'. The table has millions of
records present where the value has been set to 'Yes', and they cannot
be removed.

Regards
Marius