PRODUCT  :  Paradox Engine                        NUMBER  :  1538
  VERSION  :  3.0
       OS  :  All
     DATE  :  October 25, 1993                         PAGE  :  1/3

    TITLE  :  Example of a closest match search with Paradox Engine




  /*****************************************************************

     SRCHCLST.C
     The SETUP.C program must be compiled and run before this
     example can be executed.

     This program is a modification of the existing Paradox Engine
     3.0 example SRCHFLD.C. This program demonstrates searching for
     a closest match, rather than an exact match. The key to
     successfully searching for a closest match is to check for the
     relevant Engine error codes from the search function.

     When doing a CLOSESTRECORD search:
        PXERR_RECNOTFOUND means a record was found that is greater
        than the search value ( usually the intended result ). The
        current record is set to this record.
        PXERR_ENDOFTABLE means that no record is greater. The
        current record does not change.

     Another point worth noting is that this example conditionally
     adds an index to the table if it does not exist. This is
     because a "closest match" will be undefined unless the field
     being searched on is in order.

  *****************************************************************/

       #include <stdio.h>
       #include <dir.h>
       #include "pxengine.h"
       #define LOC __LINE__
       #define TABLENAME   "table"

       char search[] = "Value 1";  // search for a value
                                   // not in the table
       void err(int loc, int rc ); // function to display all
                                   // Engine return values

       int main(void)
       {
          char name[80];
          TABLEHANDLE  tblHandle;
          RECORDHANDLE recHandle, readBuffer;
          FIELDHANDLE  fldHandle = 1;













  PRODUCT  :  Paradox Engine                        NUMBER  :  1538
  VERSION  :  3.0
       OS  :  All
     DATE  :  October 25, 1993                         PAGE  :  2/3

    TITLE  :  Example of a closest match search with Paradox Engine




          FIELDHANDLE  indexHandles[] = { 1 };
          PXCODE       pxErr;
          RECORDNUMBER recNum;
          struct ffblk ffblk;

          PXInit();
          // don't add index if it already exists...
          if( (findfirst("table.px",&ffblk,0) !=0 ))
             // findfirst returns 0 if found
          {
             err(LOC, PXKeyAdd(TABLENAME, 1, indexHandles,
                 PRIMARY ));
             printf("Adding primary key to table\n");
          }
          err(LOC, PXTblOpen(TABLENAME, &tblHandle, 0, 0));
          err(LOC, PXRecBufOpen(tblHandle, &recHandle));
             // used for search value
          err(LOC, PXRecBufOpen(tblHandle, &readBuffer));
             // used to read found value
          err(LOC, PXPutAlpha(recHandle, fldHandle, search));

          /* Origional code which searched for an exact match on
             an Alpha field */
          /*
       if ((pxErr = PXSrchFld(tblHandle, recHandle, fldHandle,
                                 SEARCHFIRST)) != PXSUCCESS)
       {
          if (pxErr == PXERR_RECNOTFOUND)
                printf("No match found.\n");
          else
                   printf("%s\n",PXErrMsg(pxErr));
          }
          else
             printf("Match found.\n");
          */

          /* Modified code to search for closest match...    */
          if( (pxErr = PXSrchFld(tblHandle, recHandle, fldHandle,
                                 CLOSESTRECORD)) != PXSUCCESS)
          {
             if (pxErr == PXERR_RECNOTFOUND)
                //we found a record > target
             {













  PRODUCT  :  Paradox Engine                        NUMBER  :  1538
  VERSION  :  3.0
       OS  :  All
     DATE  :  October 25, 1993                         PAGE  :  3/3

    TITLE  :  Example of a closest match search with Paradox Engine




                err( LOC, PXRecNum( tblHandle, &recNum ));
                err( LOC, PXRecGet( tblHandle, readBuffer ));
                err( LOC, PXGetAlpha( readBuffer, 1, 80, name ));
                printf("The first record that is greater than\n");
                printf("the search value is record number: %d\n",
                        recNum);
                printf("Field contents: %s\n", name);
             } else { // If ... PXERR_RECNOTFOUND
                if( pxErr == PXERR_ENDOFTABLE )
                {
                   printf("no record greater\n");
                      //no record greater than target else
                } else { // if ... PXERR_ENDOFTABLE
                   printf("%d: %s\n",LOC, PXErrMsg(pxErr));
                      //some other error?
                }
             }
       } else { // else matching PXSrchFld() if
                err( LOC, PXRecNum(tblHandle, &recNum ));
                printf("Match found on record Number %d\n",
                        (int)recNum);
             }
          }

          err( LOC,PXRecBufClose(recHandle));
          err( LOC,PXTblClose(tblHandle));
          err( LOC,PXExit());

          return(pxErr);
       }

       void err(int loc, int rc )
       {
          if(rc != PXSUCCESS )
          printf("%d: %s\n", loc, PXErrMsg(rc) );
       }


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