C Language Development Kit/Snippets/Database/SearchIndexFile

From OptiWiki

Jump to: navigation, search
Description Find the search key in the index database
long SearchIndexFile( SDBFile *dbIndex, char *searchkey );
Arguments 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
char *searchkey

The key to search for in the index database file.

Returns -1L when the record is not found or on an error. The record number is returned when the searchkey has been found in the database. The record number is the record number of the database where this index is made from.
Remarks The declaration of the SDBFile needs to be static to make sure all items are initialized to 0.

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

#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());
    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 );
    printf("Close database\n");
    CloseDatabase( &dbFile );
    while( 1 )

Personal tools