export() file access problem

[gcaplan]

Hi

I'm trying to write a function to dynamically export the active db.

When I run tbl.export() I get a "file is being used by another process" error. But:

- The only windows open in Alpha are the control panel and code editor. I've re-launchec Alpha to make sure there's nothing running in the background.

- Stored export operations on the same tables run OK.

I'm stuck - I'd appreciate advice.

Here's the relevant code:

"""""""""""""""""""""""""""""""""""""""""""

function export_db( )

'List the dbf files

db_path = a5.get_name( )

all_tables_list = load_adb_def( db_path, 0 )

'Strip out the sets

dim tables_list[1] as c

for each table in all_tables_list
if regex_match( table, "^.*\.dbf$") = .t. then
tables_list[] = table.value
end if
next

'Export all fields of each table as an Excel file

dim tbl as p

for each table_file in tables_list

tbl = table.open( table_file )

'List the fields

field_list = tbl.field_info_dump( "n" )
num_fields = w_count( field_list, crlf() )

export.file = table_file.value
export.type = FILE_FORMAT_EXCEL_VERSION_4
export.names = .t.
export.fields = num_fields

i = 1

for each field_name in field_list

property_str = "export.field"+i
eval( property_str ) = field_name.value
i = i + 1

next

tbl.export( )
tbl.close( )

next

"snip...."

end function

[Tom Cone Jr]

RE: export() file access problem

Geoff,

You're working with functions I rarely use, so these questions / comments may be unhelpful.

1) " tables_list[] = table.value " --- I don't understand this form of assignment to an element in the array. Are you trying to build a list in the one element? If so, don't you need to concatenate the current table.value with previous ones? Is an element identifier needed?

2) I've had miserable luck re-using pointers. Your script uses and re-uses the "tbl" pointer. I'd suggest you delete it, and then re-dim it before each use.

I apologize in advance if none of this makes sense or helps.

-- tom

[G Gabriel]

RE: export() file access problem

Geoff:
""I've re-launchec Alpha to make sure there's nothing running in the background. ""

You did everything you can to ensure that no tables are open in the background, then you opened these tables in your script !!
"" tbl = table.open( table_file ) ""

You might want to close the tables first before initiating the export portion of your script.
Gabe

[gcaplan]

RE: export() file access problem


"""""
I don't understand this form of assignment to an element in the array.
"""""

Not sure I follow you here - this is taken straight from the Array page in the Xbasic docs - see the section "Automatically Inserting Elements into an Array". Syntax seems to work as advertised.

"""""
I've had miserable luck re-using pointers.
"""""

Worth a try, but no cigar!

delete tbl
dim tbl as p
tbl = table.open( table_file.value )
tbl.export( )

gives exactly the same result :-(

[gcaplan]

RE: export() file access problem


"""""
You might want to close the tables first before initiating the export portion of your script.
"""""

Not sure what you're suggesting here. "tbl".export() is a pointer method, so you have to have the table open to use it.

The code here is pretty much a cut-and-paste from the docs. The only difference is that I'm using the pointer for "tbl".field_info_dump before the export.

I did try Tom's suggestion of destroying the used pointer and creating a new one immediately before use, but that didn't help.

[gcaplan]

RE: export() file access problem

I am a prize ass! The problem is with the export.file assignment. I'm assigning the name of the input file rather than the output file, so it's trying to overwrite itself.

That'll teach me to try hacking in a new language after midnight.

Sorry for wasting your time...

[Tom Cone Jr]

RE: export() file access problem

Thanks. Haven't used the auto-resizing feature that has been added for arrays in recent releases, so I didn't recognize the syntax. -- tom

[Tom Cone Jr]

RE: export() file access problem

Geoff,

I see that now, too.

The line: " export.file = table_file.value "

confused me. Can't seem to find explanation in the docs.

"table_file" is an entry in the "tables_list[]" array, right? I'm curious about the ".value" syntax. Seems like a property of the array element. Is this right? Can you refer me to further information on this in the help file?

Thanks. -- tom

[gcaplan]

RE: export() file access problem

Tom

"""""
I'm curious about the "value" syntax. Seems like a property of the array element. Is this right?
"""""

I've reported a bug in the FOR EACH construct. The placeholder variable for the value on each iteration is a pointer when you would expect it to be the value itself.

Sometimes the pointer resolves to the value when you use it, sometimes you get a garbage value - the pointer itself.

Aaron suggested the "placeholder_name.value" syntax as a workaround. It reliably lets you access the value the pointer is referencing. He assures me that this will continue to work once they fix the problem.

[Tom Cone Jr]

RE: export() file access problem

Geoff,

Thanks! While you're just learning the language, you're using portions of it "old timers" like me haven't begun to use, since we're accustomed to doing things in an older, more difficult, way. So, in a round about way, this thread was useful after all.

-- tom