David

General point - index the column(s) you're performing the query on. This can
have a dramatic effect. However the bad news is that MapBasic is not very
quick with string comparison. If its still too slow then consider putting
the data in something like Access and using a custom DLL function to call up
a dialog in Access to return your x,y (or whatever).

This sounds like a pain and I suppose it is but the good thing is that it
can be completely generic and reusable. A colleague once did this with a
VB/MapX app and completely transformed the app performance (MapX isn't much
better at strings)

HTH

Paul Crisp

Syntegra
Innovation Place Delta Bank Road Newcastle NE11 9DJ
Tel 0191 461 4522 Fax 0191 460 1987


-----Original Message-----
From: Eagle, David A [mailto:[EMAIL PROTECTED]
Sent: 02 June 2003 15:56
To: MapInfo-L ([EMAIL PROTECTED])
Subject: MI-L Query Efficiency


Listers,

I have created a gazetteer query tool (in MapBasic) to query an MI table
containing 260,000 records.

The process takes a variable from my dialog and searches the place name
field (indexed) for instances LIKE it and then returns a query table
containing two columns and the object. The process then goes on to populate
an array etc, etc...However, the query process described takes 20 seconds,
this is always the case and does not vary if I move the database from its
network location to a local drive.

Any thoughts on how I can speed this process up would be greatly
appreciated...

----------------------------------------------
David A. Eagle
GIS Consultant

Atkins Design Environment
& Engineering
Cornerstone House
Stafford Park 13, Telford
Shropshire, TF3 3AZ
England
Tel:  +44 (0)1952 21 3268  * 
Fax: +44 (0)1952 20 0981  *

Email: [EMAIL PROTECTED]  *
Web: www.atkinsglobal.com <www.atkinsglobal.com>   *



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