Hello:

I have never bothered with variable substitution in SQL

statements. My tables are local. It did not seem to quite fit, and

there is my second question below.

However, I have two issues.

I have a lot of cases where I have multiple options for which

the end user might only select some of them. On one report that I am

currently updating for other reasons, there are three: date low, date

high, and client. All of these are optional.

I could write for the eight cases

select * from catx ...

select * from catx where trndate>=?datelow ...

select * from catx where trndate<=?datehigh ...

select * from catx where trndate>=?datelow and trndate<=?datehigh ...

select * from catx where clcode=?theclcode ...

select * from catx where trndate>=?datelow and clcode=?theclcode ...

select * from catx where trndate<=?datehigh and clcode=?theclcode ...

select * from catx where trndate>=?datelow and trndate<=?datehigh and

clcode=?theclcode ...

and this will work, but this would not be practical in cases where

there are more optional variables. One report has five.

To get around this, I build the expression as in this example:

* Build where expression.

local thewhere

thewhere=""

thewhere=thewhere+"trndate>=?this.datelow and trndate<=?this.datehigh"

if !empty(this.theclcode)

thewhere=thewhere+" and clcode=?this.theclcode"

endif

* Get Possible Transactions

SQLSEL * from catx;

where &thewhere;

into cursor rawdata readwrite nofilter

My first question is whether this is safe from a SQL injection

attack. It appears so, but I may be overlooking something.

My second question is whether it is possible to have this sort

of protection for other statements. I use browses, and the

substitution does not work there, that is

browse for clcode=?theclcode

does not work. (Missing operand error)

With browses, I have some with even more optional values. One

has twelve. 4096 different versions of a statement is really too much.

If I do it for one (SQL), I want to do it for the other (browses).

Sincerely,

Gene Wirchenko

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