How To Append Records from Any Delimited File with Memo Data

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Article ID: 140294 - View products that this article applies to.
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SUMMARY

This article shows by example how to append records from any delimited ASCII text file into a predefined FoxPro table or .dbf file.

The intent of the program listed in this article is twofold. The first is to address the inability of the APPEND command to read data into a memo field. The second is to provide a wider range of support for source file formats that the APPEND command does not support.

MORE INFORMATION

Here's an excerpt from the Visual FoxPro APPEND FROM Help Topic:
"A delimited file is an ASCII text file in which each record ends with a carriage return and linefeed. Field contents are by default assumed to be separated from each other by commas, and character field values to be additionally delimited by double quotation marks."
The program listed in this article does not require linefeeds after the carriage return, nor does it require that character data be delimited by double quotation marks. Also, files do not have to be terminated with an end-of-file marker (^Z), but the program will work fine if the end-of-file marker is present. This flexibility is necessary because many applications do not export their data in a format suitable for FoxPro's APPEND FROM command.

Numeric, Float, Double, Integer, Currency, Date, and Memo fields from delimited files can be imported if the data is in proper format. The date format defaults to mm/dd/yy. Including the century portion of a date is optional. FoxPro will import a date, such as 12/25/95, that doesn't include the century assuming the date is in the twentieth century.

Date delimiters can be any non-numeric character except the delimiter that separates the fields in the delimited file. Dates in other formats can be imported if their format matches a date format available in SET DATE. To import dates that are not in the default format, issue SET DATE with the proper date format before using the program listed in this article (Appendm.prg). To test if a date format can be successfully imported, use it with CTOD(). If the date is acceptable to CTOD(), the date will import properly.

Character strings with a length in excess of 10,000 characters have been tested and work fine when imported into a memo field.

NOTE: Do not use a delimiting character that appears in the actual data.

Sample Code

     Appendm.prg
    
     Purpose:
    
       * Append records from any delimited ASCII text file into a
       * predefined FoxPro table or .dbf file. The intent of this program
       * is twofold. The first is to address the inability of the
       * APPEND command to read in data into a memo field. The second
       * is to provide a wider range of support for source file formats.
    
     Syntax:
    
       DO AppendM [WITH <expC1>, <expC2&>[, <expC3>[, <expC4>]]]
    
     Parameters:
    
      <expC1>
    
     *   Specify the full name of the ASCII text file to append from
     *   with extension. If this parameter is used, then <expC2> and
     *   optionally <expC3> must be specified also. If this
     *   parameter is not specified, the user will be prompted for the
     *   file.
    
      <expC2>
    
     *  Specify the field-delimiting character. This parameter must
     *  be used if <expC1> is specified. If <expC1> is not 
     *  specified, this parameter is ignored.
           
         Samples:    ','    = COMMA
                     CHR(9) = TAB

       <expC3>
    
    *  Specify the character field delimiting character. Use the
    *  null string ("") for none. This parameter is optional if
    *  <expC1> is specified. If <expC1> is not specified, this
    *  parameter is ignored.
    
      <expC4>
    
    *  Specify the name of the table or .dbf file to append to. If the
    *  extension is not specified, .dbf is assumed. If a table or .dbf
    *  file is open in the current work area, this parameter will be
    *  ignored and the open table will be used.
    
     Examples:
    
    *  For full prompting:
    
          DO AppendM
    
    *  For a source file with comma-delimited fields and double-quotation-
    *  mark delimited character fields:
    
          DO AppendM WITH 'SRCFILE.TXT', ',', '"'
    
    *  For a source file with tab-delimited fields and no character
    *  field delimiter:
    
          DO AppendM WITH 'SRCFILE.TXT', CHR(9)
    
    *  For a source file with comma-delimited fields and double-quotation-
    *  mark delimited character fields with the current work area unused:
    
          DO AppendM WITH 'SRCFILE.TXT', ',', '"', 'DESTFILE.DBF'
    
     Notes:
    
    *  Before using this program, ensure that the target table or
    * .dbf file is structured to accept the data from the source
    *  file, and ensure that the source file is in ASCII file format.
    
    *  Each record in the source file must be terminated with a
    *  carriage return (CR). Linefeeds (LF) following a CR are
    *  also supported. The program will address text files with
    *  any field delimiters. Character data fields may optionally be
    *  delimited. An end-of-file marker (^Z) is supported but not
    *  required.
                                                                          
   PARAMETERS cTextFile, cFieldDelim, cChrFldDelim, cTableFile
                                            
   IF TYPE( "cTextFile" ) = 'L'
                                                  
      cTextFile = ''
                                                   
   ENDIF
   IF TYPE( "cFieldDelim" ) = 'L'
                                                  
      cFieldDelim = ''                              
                      
   ENDIF
   IF TYPE( "cChrFldDelim" ) = 'L'
                                                  
      cChrFldDelim = ''
                                                    
   ENDIF
   IF TYPE( "cTableFile" ) = 'L'
                                                  
      cTableFile = ''
                                                    
   ENDIF                      
                          
    *  Attempt to get and/or open the table or .dbf file
    *  If successful, continue; otherwise, Return
    
   IF USED()
                                                 
      cDBF_File = ALIAS()
                                                    
   ELSE
                                                  
      IF EMPTY( cTableFile )
         cDBF_File = GETFILE( 'DBF', 'Append to:')
      ELSE
         IF !FILE( cTableFile ) AND !FILE( cTableFile + '.DBF' )
            cDBF_File = GETFILE( 'DBF', 'Append to:')
         ELSE
            cDBF_File = cTableFile
         ENDIF
      ENDIF
      IF !EMPTY( cDBF_File )
         USE (cDBF_File)
      ELSE
         ?? CHR(7)
         WAIT WINDOW "No Table/DBF Selected to Append To!"
         RETURN
      ENDIF
                                                    
   ENDIF
                                                
    *  Attempt to get ASCII text file
    *  If successful, continue; otherwise, Return
    
   IF EMPTY( cTextFile )
                                                  
      cTXT_File = GETFILE( 'TXT', 'Source:')
                                                    
   ELSE
                                                  
      IF !FILE( cTextFile )
         cTXT_File = GETFILE( 'TXT', 'Source:')
      ELSE
         cTXT_File = cTextFile
      ENDIF
                                                    
   ENDIF
   IF EMPTY( cTXT_File )
                                                 
      ?? CHR(7)
      WAIT WINDOW "No Text File Selected to Append From!"
      RETURN
                                                    
   ENDIF
                          
    *  Verify Delimiting Characters. If successful,
    *  continue; otherwise, Return
    
   IF EMPTY( cTextFile )
                                                  
      DEFINE WINDOW wGetDelims ;
         FROM 1,1 TO 15,60 ;
         TITLE "Delimiters" ;
         NOCLOSE NOFLOAT NOGROW NOMDI NOMINIMIZE NOSHADOW NOZOOM
      MOVE WINDOW wGetDelims CENTER
      ACTIVATE WINDOW wGetDelims NOSHOW
      CLEAR
      @3,10 SAY "Press the Field Delimiting Character"
      @5,10 SAY "ie.. COMMA = <,> or TAB = <TAB KEY>"
      @7,29 say "" COLOR I
      ACTIVATE WINDOW wGetDelims
      nFieldDelim = INKEY(0,'S')
      IF nFieldDelim = 9 or nFieldDelim > 32 and nFieldDelim < 127
         cFieldDelim = CHR( nFieldDelim )
      ENDIF
      @3,5 SAY "Press the Character Field Delimiting Character"
      @5,6 SAY "Typically DOUBLE-QUOTE, Press ENTER for None"
      @7,29 say "" COLOR I
      nChrFldDelim = INKEY(0,'S')
      CLEAR
      IF nChrFldDelim > 32 and nChrFldDelim < 127
         cChrFldDelim =CHR( nChrFldDelim )
         ELSE
           cChrFldDelim = ""    && No delimiter
      ENDIF
      DEACTIVATE WINDOW wGetDelims NOSHOW
      RELEASE WINDOW wGetDelims
                                                    
   ENDIF
                                          
   IF LEN( cFieldDelim ) = 0
                                              
      ?? CHR(7)
      WAIT WINDOW "No Field Delimiting character Specified!"
      RETURN
                                                    
   ENDIF
                                            
    *  Attempt to open text file with low-level handle.
    *  If the test is successful, continue; otherwise,
    *  report reason for failure.
    
   nFileHandle = FOPEN( cTXT_File )
   IF nFileHandle < 0
                      
                            
      DO ErrHand WITH FERROR(), cTXT_File
      RETURN .F.
                              
                      
   ENDIF
    
    *  Create an array of database structure.
    *  Determine number of records in array for
    *  loop counting.
    
   =AFIELDS( aStructure )
   nRows = ALEN( aStructure, 1 )
                                               
    *  Begin DO WHILE loop and continue until end of
    *  file marker is reached in text file.
                                             
   nFileSize = FSEEK( nFileHandle, 0, 2 )
   = FSEEK( nFileHandle, 0, 0 )
   nBytesRead = 0
   RecsApnd = 0
   lChrFldDelimFlag = LEN(cChrFldDelim ) # 0
   WAIT WINDOW ' Records Appended: ' + LTRIM( STR( RecsApnd )) + ;
                      
                            
     CHR(13) + ' Percent Completed: ' + ;
     LTRIM( STR( nBytesRead/nFileSize 100)) NOWAIT
                              
                      
   DO WHILE !FEOF( nFileHandle )
                      
                            
      APPEND BLANK
      FOR i = 1 TO nRows
         cFieldData = ReadField( cFieldDelim, cChrFldDelim )
         DO CASE
            CASE aStructure[i,2] $ "NY"
              REPLACE &aStructure[i,1] WITH VAL( cFieldData )
            CASE aStructure[i,2] = "D"
               REPLACE &aStructure[i,1] WITH CTOD( cFieldData )
             OTHERWISE
               REPLACE &aStructure[i,1] WITH cFieldData
         ENDCASE
           WAIT WINDOW ' Records Appended: ' + LTRIM( STR( RecsApnd )) + ;
           CHR(13) + ' Percent Completed: ' +;
           LTRIM( STR( nBytesRead/nFileSize 100 )) NOWAIT
      ENDFOR
      RecsApnd = RecsApnd + 1
                              
                      
   ENDDO
   =FCLOSE( nFileHandle )
   WAIT WINDOW ' Records Appended: ' + LTRIM( STR( RecsApnd )) + ;
                      
                            
     CHR(13) + ' Percent Completed: ' + ;
     LTRIM( STR( nBytesRead/nFileSize 100)) NOWAIT
                                           
   RETURN
                      
   FUNCTION ReadField
   PARAMETER cFieldDelim, cChrFldDelim
   cAccumText = ""
   lFldDelimFlag = .F.
   DO WHILE !lFldDelimFlag AND !FEOF( nFileHandle )
      cSingle = FREAD( nFileHandle, 1 )
      nBytesRead = nBytesRead + 1
      IF cSingle = cFieldDelim OR cSingle = CHR(13) OR ;
         IIF( lChrFldDelimFlag, cSingle = cChrFldDelim, .F. )
                            
         IF cSingle = CHR(13)
            cSingle = FREAD( nFileHandle, 1 )
            nBytesRead = nBytesRead + 1
            IF cSingle = CHR(10)
               cSingle = FREAD( nFileHandle, 1 )
               nBytesRead = nBytesRead + 1
               IF !(cSingle = CHR(26) OR ASC(cSingle) = 0)
                  =FSEEK( nFileHandle, -1, 1 )
                  nBytesRead = nBytesRead - 1
               ENDIF
            ELSE
               IF !(cSingle = CHR(26) OR ASC(cSingle) = 0)
                 =FSEEK( nFileHandle, -1, 1 )
                 nBytesRead = nBytesRead - 1
               ENDIF
            ENDIF
            lFldDelimFlag = .T.
         ENDIF
         IF cSingle = cFieldDelim
            lFldDelimFlag = .T.
         ENDIF
         cSingle = ""
      ELSE
         cAccumText = cAccumText + cSingle
      ENDIF
                                            
   ENDDO
   RETURN cAccumText
                        
   PROCEDURE ErrHand
   PARAMETERS nError, cFileName
   DO CASE
   CASE nError = 2
                                                 
      cReason = "File not found: " + cFileName
                                                    
   CASE nError = 4
                                                  
      cReason = "Unable to open ' + cFileName + '. Too many files open"
                      
   CASE nError = 5
                                                  
      cReason = "File access denied: " + cFileName
                                                    
   CASE nError = 6
                                                  
      cReason = "Error: Invalid file handle given"
                                                    
   CASE nError = 8
                                                  
      cReason = "Error: Out of memory"
                                                    
   CASE nError = 25
                      
      cReason = "Seek error (can't seek before start of file)"
                                                   
   CASE nError = 29
                      
      cReason = "Error: Disk is full"
                                                    
   CASE nError = 31
                                                  
      cReason = "Error opening file: " + cFileName
                                                    
   ENDCASE
   ?? CHR(7)
   WAIT WINDOW cReason
   RETURN
                                            
    EOF Appendm.prg
				

Properties

Article ID: 140294 - Last Review: October 27, 2006 - Revision: 2.3
APPLIES TO
  • Microsoft Visual FoxPro 3.0 Standard Edition
  • Microsoft Visual FoxPro 6.0 Professional Edition
  • Microsoft FoxPro 2.5b
  • Microsoft FoxPro 2.5a
  • Microsoft FoxPro 2.5b
  • Microsoft FoxPro 2.6 Standard Edition
  • Microsoft FoxPro 2.6a Standard Edition
  • Microsoft FoxPro 2.5b for MS-DOS
  • Microsoft FoxPro 2.5a
  • Microsoft FoxPro 2.5b for MS-DOS
  • Microsoft FoxPro 2.6 for MS-DOS
  • Microsoft FoxPro 2.6a Standard Edition
  • Microsoft FoxPro 2.5b for Macintosh
  • Microsoft Visual FoxPro 2.5c for Macintosh
  • Microsoft FoxPro 2.6a Professional Edition for Macintosh
Keywords: 
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