The LA Fox Developer Newsletter

September 1995

Error Trapping (Con't from page 3)

Hot Tip .

Making Browse Key Faster

Using Undocumented Syntax

Requirements

by Wayne Snyder, 71 754,1 553

At one time or another, almost everyone needs to do

a lookup on address. The requirement I had was to

aHowthe userto name a street, streettype like DR, LN,

PKVVY, HWY, etc., street direction like E,W, N, S, as

well as the house number to get to a browse screen.

The user may want the browse to include all streets

whose name begins with “CANNON” and whose street

type is "BLVD", so that all properties for CANNON

BLVD, CANNON TEMPLE BLVD, etc. would popu-

late the browse window.

My solution was to use code like

My assumption is that the street name is the item

which is most likely to be known. When running the

program however, bad response became an issue. If

I entered “CANNON” as the street name with every-

thing else empty, response was fast. If I add I

character to ANY other field, things got slower. Two

characters made it slower still.

In trying to debug the problem I created a small function

which always returned TRUE, but added one to a local

variable. I put this function in the BROWSE FOR clause

so that after the browse was through, I could see how

many records were beEng compared in the FOR clause

of the browse. Sure enough, the more characters

entered in houseno, for instance, the more records were

being compared in the FOR clause, until a full Table

search was being performed. I knew that there were 100

records with a street name of “CANNON”, but all I million

records were being searched. This is not what I ex-

pected at all, but fortunately the solution is very simple.

PUT THE KEY CLAUSE IN FRONT OF THE FOR

CLAUSE, and life will be good again. Imagine that!!!....

I could not find any documentation which suggests the

order of the clauses wou’d make any difference, but it

surely does. The good code looks like

Boy, is this fast!!!! I hope this tip might save you several

days of debugging time! This problem exists in FPW

2.5b and FPW 2.6 and FPW 2.6a.

It Can’t Get Any Easier......

We’ve come up with an easy way to submit articles to

the LA Fox Developer Newsletter one that has

been overlooked for a long time.

You can submit your articles to either Chuck Williams

(72330,2326) or Barry Lee (72723,3422) on

Compuserve.

These articles can be on any FoxPro-related topic,

whether it concerns a new technique you’ve discov-

ered, a certain development technique you may favor

over others, book reviews, etc.

The quality of this newsletter really depends on the

members that support it, not just read it. And I think

we’d all be surprised by the useful information that

could be circulated around the membership.

So.

How bout it?

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