C Language Development Kit/Snippets/Database/OpenIndexFile

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Description Open an index database file.
Syntax
int OpenIndexFile( const char *indexfilename, short keysize, SDBFile *dbFile );
Arguments
const char *indexfilename

The filename of the index database file.

short keysize

The length of the search key.

SDBFile *dbIndex dbIndex is pointer to a structure that holds information about the index file. The SDBFile structure is defined as followed:

typedef struct
{
    short  sRecSz;        // record size of database
    int    fd;            // real handle to the open file
    long   lCurrRecord;   // current record number
    long   lTotalRecords; // total amount of records
    int    bOpen;         // check to see if db is open or closed
}SDBFile;
Returns
TRUE On success.
FLASE On failure.
Remarks The declaration of the SDBFile needs to be static to make sure all items are initialized to 0.

When the OpenIndexFile() functions returns FALSE the error code can be obtained by making a call to GetDBErrorCode() function.

Example
#include "lib.h"
#include <stdio.h>
#include "database.h"  //Holds the database functions
 
void main( void )
{
    static SDBFile dbFile;  // static initializes all items to 0
    static SDBFile dbIndex; // static initializes all items to 0
    long recno;
    int i;
    char record[32 + 1];
 
    printf("\fCreate database\n");
    if( !CreateDatabase("file1.txt", 32, &dbFile ))
        printf("Error code = %ld\n", GetDBErrorCode());
 
    memset( record, '\0', sizeof( record ));
    printf("Write 10 records\n");
    for( i = 9; i > -1; i-- )
    {
        sprintf(record, "%01d23456789012345678901234567890\r\n", i);
        if( !WriteRecord( &dbFile, record, WRITE_APPEND ))
        {
            printf("Error code = %ld\n", GetDBErrorCode());
            break;
        }
    }
 
    if( !CreateIndexFile( &dbFile, 0, 2, (char*)"file_idx.txt", &dbIndex ))
        printf("Error code = %ld\n", GetDBErrorCode());
 
    if( (recno = SearchIndexFile( &dbIndex,(char*)"62")) == -1L)
        printf("Error code = %ld\n", GetDBErrorCode());
 
    if( !GotoRecord( &dbFile, recno ))
        printf("Error code = %ld\n", GetDBErrorCode());
    if( !ReadCurrentRecord( &dbFile, record ))
        printf("Error code = %ld\n", GetDBErrorCode());
    printf("recnr = %ld, %-30.30s\n", recno, record );
 
    printf("Close Index file\n");
    CloseDatabase( &dbIndex );
 
    if( !WriteRecord(&dbFile,(char*)"593456789012345678901234567890\r\n",WRITE_APPEND))
        printf("Error code = %ld\n", GetDBErrorCode());
 
    printf("Open Index file\n");
    if( !OpenIndexFile( (char*)"file_idx.txt", 2, &dbIndex ))
        printf("Error code = %ld\n", GetDBErrorCode());
 
    if( !AddNewSearchkeyToIndex( &dbIndex, (char*)"59", GetCurrentRecord( &dbFile )))
        printf("Error code = %ld\n", GetDBErrorCode());
 
    if( (recno = SearchIndexFile( &dbIndex,(char*)"59")) == -1L)
        printf("Error code = %ld\n", GetDBErrorCode());
 
    if( !GotoRecord( &dbFile, recno ))
        printf("Error code = %ld\n", GetDBErrorCode());
    if( !ReadCurrentRecord( &dbFile, record ))
        printf("Error code = %ld\n", GetDBErrorCode());
    printf("recnr = %ld, %-30.30s\n", recno, record );
 
    printf("Close Index file\n");
    CloseDatabase( &dbIndex );
 
    printf("Close database\n");
    CloseDatabase( &dbFile );
 
    while( 1 )
        idle();
}


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