Re: Do I understand form optimization correctly?
- From: "John Welch" <j+ohnw+elch@cal+central.com (remove +'s)>
- Date: Mon, 1 Aug 2005 18:09:13 -0700
> To answer your question, no, it won't matter how you execute the
> queries on an Access database. Access is file based, not server based.
> If you run any query on the table, the entire table is brought down to
> your machine, and the query is executed.
I don't think this is correct, actually. That's why I was asking: because a
lot of people say that each query has to retreive the 'whole table', but I
think if the fields are indexed, then only the index has to be sent. Can
someone who really knows settle this?
>
>
> Chris Nebinger
>
>
> John Welch (remove +'s) wrote:
>> I'm developing my first multi-user application, and have been reading a
>> lot
>> about the basics of multi-user optimization (ADH vol 2, this newsgroup's
>> archives, etc.). I've decided to go with a file server system (mdb
>> backend
>> on network), and I want to design it so that it runs efficiently. There
>> will
>> be 5-10 concurrent users and ~30,000 records. I'm trying to optimize it
>> by
>> addressing the most important issues first. I've been focusing on the
>> idea
>> of having forms 'serve up' only a few records at a time, rather than a
>> whole
>> table's worth, and I wonder if some of you pros can help me confirm that
>> I'm
>> understanding it correctly. So here goes:
>>
>> 1) If I bind a form to a query that filters the records with a 'WHERE'
>> clause, and the field in the 'WHERE' is indexed, the backend will send
>> the
>> whole index across the wire, but not "the whole table" as some people
>> seem
>> to say, right? Then the front end will search the index and request the
>> records that match the WHERE clause, and then only those records will be
>> sent. Is that right?
>>
>> If this is correct, then a lot less network traffic will be created, but
>> there will be a lot of searching of indexes: every time the user
>> 'navigates'
>> to a new record a new query is run. So does that mean that searching
>> large
>> indices is faster than sending lots of data? Or does it depend on the
>> details of the network?
>>
>> 2) In the WHERE clause that limits the recordsource, does using "LIKE"
>> slow
>> things down a lot? For example, to get all customers whose last names
>> start
>> with "smi". How about if I do something like "SELECT top 10 ... order
>> by
>> myIndexedField" ? Will that be a lot slower than limiting records with
>> 'WHERE'?
>>
>> 3) For subform recordsources, I usually use saved queries with "WHERE
>> myfield = forms!parentform.control_bound_to_PK_field". Is this a good way
>> to
>> go, and is it a lot better than using the "link master/child" fields
>> properties, for the same reason as in (1) above?
>>
>> Thanks very much in advance. This newsgroup is wonderful!
>> -john
>
.
- References:
- Do I understand form optimization correctly?
- From: John Welch
- Re: Do I understand form optimization correctly?
- From: chris . nebinger
- Do I understand form optimization correctly?
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