Can't pass array function result as parameter

[Jerry Daniels]

James,

The fix to this bug has been coded and unit tested. I've posted it to  
the Constellation Basecamp Support Site. Please let me know how it  
works for you.

Best,

Jerry Daniels


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On Apr 1, 2006, at 10:40 AM, James Spencer wrote:

>
> On Apr 1, 2006, at 3:25 AM, David Burgun wrote:
>
>> There's really no need to copy it entry by entry, you can just  
>> copy the whole array as in:
>>
>> put LibGetArray() into myArray1
>>
>> put LibAnotherFunction(myArray1) into myArray2  --Here you could  
>> put it back into Array1
>>
>> I do this all the time.
>>
>> What you can't do is this:
>>
>> put LibAnotherFunction (LibGetArray()) into myArrayX
>
> Just to bring this full circle, I finally figured out what was  
> going on.  I'm going to take the time to sum up what I figured out  
> because it may save someone else some frustration.
>
> Background:
> Being more specific than I have been, I am testing for someone else  
> a library of routines for accessing a MySQL database, something  
> similar to Blue Mango's libDatabase (it's not mine which is why  
> I've been a little careful about including any code from the  
> library here).  The test involves a simple database containing  
> records of books, things like Title, Author, ISBN, etc.  I was  
> trying to get a record (representing a single book) from a  
> database, modify it and then insert the modified record back into  
> the database as a new record.  The call to insert the record into  
> the database was failing silently.
>
> My original problem:
> In my code, I was doing exactly what Dave suggests above.  I called  
> the equivalent of LibGetArray(), specifically calling a library  
> function which returned the current record in the form of an array  
> where each element of the array is a field of the record.  I was  
> putting this array into a local variable as Dave suggests above and  
> the debugger showed that the local variable correctly contained a  
> valid array.  I then modified one element, the title of the book,  
> in the array (in the local variable) and then passed the local  
> variable to the equivalent of LibAnotherFunction(), specifically a  
> handler which inserts a record in the database with the values  
> contained in the array passed to it.  My specific code which was  
> failing:
>
> on mouseUp
>
>     -- duplicates the current record in the database, appending
>     -- "(DUPLICATE)" to the book title.
>
>     local tRecordSet, tCurrentRecord, tTitle
>     local tErrorNo,tErrorString
>
>     try
> 	-- cRecordSet is a custom property containing a reference to
> 	-- to the current database "cursor", i.e. a set of records
> 	-- from the database
>         put the cRecordSet of this stack into tRecordSet
> 	
> 	-- the following puts the current record data into a
> 	-- Rev array using the database column names as the indices
>         put dbGetRecordData(tRecordSet) into tCurrentRecord
>
>         -- alter the title so we can see this is a duplicate book
>         put tCurrentRecord["Title"] into tTitle
>         put "(DUPLICATE)" after tTitle
>         put tTitle into tCurrentRecord["Title"]
>
> 	-- dbInsert expects the name of a MySQL table and a Rev
> 	-- array containing the new record data, indexed by
> 	-- database column names.  This fails
>         dbInsert "books", tCurrentRecord
>
>         -- code to update the display omitted
>
>     catch pException
> 	-- the above fails silently: we never catch an error here
>         put item 1 of line 1 of pException into tErrorNo
>         put item 2 of line 1 of pException into tErrorString
>         answer "ERROR: Unable to copy the book.  Error = " &  
> tErrorNo & \
>                 " (" & tErrorString & ")!"
>     end try
>
> end mouseUp
>
> What made this VERY frustrating was that I would walk through the  
> above code and step into dbInsert in the debugger and what it  
> showed was that tCurrentRecord was correctly being set by  
> dbGetRecordData, the Title of the book was correctly getting  
> changed in tCurrentRecord and tCurrentRecord was valid in the line  
> calling dbInsert but in dbInsert, the second parameter was showing  
> in the debugger as empty.
>
> The solution:
> In the end, the problem was NOT with the array passing but rather  
> three unrelated bugs.
>
> The first arose because I was using Constellation's debugger and  
> variable display.  There is apparently a minor bug in how it shows  
> arrays passed as  parameters: in dbInsert it was showing the second  
> parameter as empty even though I knew I was passing a valid array.   
> In fact, while Constellation's display showed the parameter as  
> empty, Rev's variable watcher, which I finally opened this morning,  
> shows that the parameter is valid containing exactly what I passed.
>
> The other two bugs are related and I'm not sure if they are in the  
> library I'm testing or in the Rev database library.  First, some of  
> the elements in the array returned from dbGetCurrentRecord were  
> empty and I was passing those empty elements back to dbInsert.   
> This causes the insertion to fail with a MySQL syntax error,  
> although I haven't completely figured out why.  Whatever, just to  
> complete the perfect storm, dbInsert has a bug in that it looks for  
> "revdberr" in the result of the SQL command which did the insert  
> and as the error returned by MySQL did not contain this, no error  
> was being thrown.
>
> Bottom line is that at this point, as I already discovered by  
> happenstance, my code works by copying the array element by element  
> checking that the element is not empty (I suppose I could also  
> simply delete the empty elements from tCurrentRecord), and I will  
> report the minor bugs that I found to both Constellation and the  
> library author.
>
> Thank you all for your help in working this out.
>
> Spence
>
> James P. Spencer
> Rochester, MN
>
> jspencer78 at mac.com
>
> "Badges??  We don't need no stinkin badges!"
>
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