Dear Bill I am not aware of there being a maximum.
In terms of an optimum the less fields you index on the quicker an index will be updated. However your application might gain enormously by having more indexes so it is difficult to talk of an optimum. In general our experience is that adding one record at a time this is not an issue. However if you are adding a lot at a time and no other users need access while you are doing this, then it is worth dropping the indexes, adding the records, then creating the indexes as a seperate operation. Also keep the index as short as possible. MapInfo will index on the first 127 bytes of a field. If you do not need this length it could be worth maintaining a seperate shorter field in your database, and index on this. It takes less than half the time to reindex a field that is half the length. The same advantage applies when retrieving a record from the index. Try and store numeric values in smallint,integer or float as these indexes will be shorter than a decimal one. If there is a maximum then it is certainly a lot greater than 3 and we have not yet hit it. Regards Bob mapsbydesign.co.uk In message <[EMAIL PROTECTED]>, Data Directions <[EMAIL PROTECTED]> writes > >I have searched the MapInfo manuals and knowledge base but cannot find an >answer to the following: > >Is there an optimal (or maximum) number of indexes that can be applied to >columns within a MapInfo table before their use is ineffective. > >I seem to recall a maximum of three indexes per table, but may be mistaken. > >If someone knows, could they please advise, along with the rationale for (or >if necessary, formula to calculate) the answer. > >Many thanks, > >Bill > >--------------------------------------------------------------------- >List hosting provided by Directions Magazine | www.directionsmag.com | >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] >Message number: 2676 -- bob young --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 2679
