Q115731: How to Read Memo Field Data from Delimited ASCII Files
Article: Q115731
Product(s): Microsoft FoxPro
Version(s): 2.50 2.50a 2.50b 2.60 | 2.00 2.5
Operating System(s):
Keyword(s): kbcode
Last Modified: 26-AUG-1999
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The information in this article applies to:
- Microsoft Visual FoxPro for Windows, version 3.0
- Microsoft FoxPro for Windows, versions 2.5, 2.5a, 2.5b, 2.6
- Microsoft FoxPro for MS-DOS, versions 2.5, 2.5a, 2.5b, 2.6
- Microsoft FoxPro for Macintosh, versions 2.5b, 2.5c
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SUMMARY
=======
FoxPro uses the APPEND FROM command to read in text stored in various types of
delimited ASCII file formats. The APPEND FROM command will read in all data with
the exception of any memo field data. This data is completely ignored by the
APPEND FROM command. The suggested work around has always been to read the file
in using low-level I/O. This requires writing a program that will read the data
in 1 byte at a time. The program shown below will work with almost any type of
delimited ASCII text file and will read in the memo field data that in the past
had been left out.
MORE INFORMATION
================
Sample Code
-----------
***************************************************
* Append data from any delimited ASCII file into
* a predefined FoxPro database file. The intent
* is to read in memo field data, but the program
* will also address files with varying delimiters.
* This program assumes that the target database
* file is currently in use, used exclusively, and
* in the current work area.
***************************************************
PARAMETERS text_file, char_delimiter, field_delimiter
***************************************************
* Create an array of database structure.
* Determine number of records in array for FOR
* loop counting.
***************************************************
=AFIELDS(structure)
rows = ALEN(structure,1)
***************************************************
* Attempt to open text file with low-level handle.
* If the test is successful, continue; otherwise,
* report reason for failure.
***************************************************
file_handle = FOPEN(text_file)
IF file_handle < 0
DO errhand WITH FERROR()
RETURN .F.
ENDIF
***************************************************
* Begin DO WHILE loop and continue until end of
* file marker is reached in text file.
***************************************************
DO WHILE !FEOF(file_handle)
APPEND BLANK
FOR i = 1 TO rows
IF structure[i,2] = "N"
=readnum("",0)
ELSE
=readchar("",0)
ENDIF
ENDFOR
ENDDO
=FCLOSE(file_handle)
***************************************************
* Read numeric field data into corresponding
* field in database.
************************************************
FUNCTION readnum
PARAMETERS accum_text, count_comma
DO WHILE count_comma < 1
single = FREAD(file_handle,1)
IF single = field_delimiter OR single = CHR(13)
single = ""
count_comma = count_comma + 1
IF count_comma < 1 AND i > rows
=FSEEK(file_handle,1,1)
ENDIF
ELSE
accum_text = accum_text + single
ENDIF
ENDDO
REPLACE &structure[i,1] WITH VAL(accum_text)
accum_text = ""
RETURN
***************************************************
* Read all field types in as character except
* numeric fields.
***************************************************
FUNCTION readchar
PARAMETERS accum_text, count_quotes
DO WHILE count_quotes < 2 AND !FEOF(file_handle)
single = FREAD(file_handle,1)
IF single = char_delimiter
single = ""
count_quotes = count_quotes + 1
IF count_quotes >= 2
x=FREAD(file_handle,1)
IF x = CHR(13)
=FSEEK(file_handle,1,1)
ENDIF
ENDIF
ELSE
accum_text = accum_text + single
ENDIF
ENDDO
REPLACE &structure[i,1] WITH accum_text
accum_text = ""
RETURN
***************************************************
* Error handling routine
***************************************************
FUNCTION errhand
PARAMETERS error
DO CASE
CASE error = 2
reason = "File not found"
CASE error = 4
reason = "Too many files open"
CASE error = 5
reason = "File access denied"
CASE error = 6
reason = "Invalid file handle given"
CASE error = 8
reason = "Out of memory"
CASE error = 25
reason = "Seek error (can't seek before start of file)"
CASE error = 29
reason = "Disk is full"
CASE error = 31
reason = "Error opening file"
ENDCASE
WAIT WINDOW "Cannot open file: "+reason
NOTE: This program assumes an ASCII file format as the source file. If there is
an end-of-file (EOF) marker in this file, the program will not terminate and
will remain in an infinite loop until the ESC key is pressed. Despite this minor
problem, the data will still be read correctly. To avoid this problem, remove
the EOF marker with a text editor.
Additional query words: VFoxWin FoxDos FoxWin 2.00
======================================================================
Keywords : kbcode
Technology : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbFoxproSearch kbZNotKeyword3 kbFoxPro250bMac kbFoxPro250cMac kbFoxPro250DOS kbFoxPro250aDOS kbFoxPro250bDOS kbFoxPro260DOS kbFoxPro260 kbFoxPro250 kbFoxPro250a kbFoxPro250b kbVFP300
Version : 2.50 2.50a 2.50b 2.60 | 2.00 2.5
=============================================================================
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