Inércia Sensorial pressed the little lettered thingies in this order...
> I am sorry, maybe going a little off-message here, but what would do you
> mean by eliminate 'table-scans'?
>
> --
What is typically referred to as a "table scan" is any operation that
requires scanning of the entire table to get the results (i.e. querying on
non-indexed fields). Sometimes it isn't possible to avoid this behavior,
but you should try to limit queries (especially on large tables) to indexed
fields as much as possible. For example:
Create two tables
1) with the fields "Name" and "ID" where the "ID" field is indexed
2) with the fields "ID" (ID from the previous table instead of the "Name"
of the item) and fields for the other parameters
To query the second table for data, you create a drop-down box that
shows users the "Name", but sends the SQL server the ID number (both
retrieved from the first, smaller table). The resulting query on your larger
table is:
WHERE ID='$ID'
Which is multitudes faster (the field is indexed, therefore the SQL server
knows exactly where to find it/them and doesn't have to sort through
every record) than:
WHERE Name='$Name'
Where the "Name" field is not indexed (the SQL server has to search
every record in the database for a match)
There are several cases and uses of indexes where indexing can slow
your server down considerably, but that's WAY beyond the scope of an
e-mail message.
If you want to find out more about that stuff, I recommend the book
called "MySQL" by Paul DuBois.
Have fun...
Christopher Ostmo
a.k.a. [EMAIL PROTECTED]
AppIdeas.com
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