MarkusRechberger/BerkeleyDB

BerkeleyDB

www.sleepycat.com

Berkeleydb ist eine lokale Datenbank für C, Java, Perl und einige andere Programmiersprachen.

berkeleydb funktioniert mit keys und datenpayload..
primary key hat hier diesbezüglich eine ganz andere meinung z.b.:

create table foobar(id int primary key, name char[10], nachname[10]);
->
key ist id
payload name, nachname welche in einem struct verpackt sein müssen.
demnach kann man das ganze auch nicht so einfach nach einem name bzw nachname durchsuchen (In der Doku gibts noch genauere Informationen wie man 2 Keys verwenden kann). BerkeleyDB ist keine relationale datenbank.

codeschnipsel:
#include <stdio.h>
#include "geodata.h"
#include <db.h>

#define DATABASE "geo.db"

int main(int argc,char **argv){
        DBT key,data;
        DB *dbp;
        char keybuffer[3];
        char countrybuffer[4];


        int i,d,ret;

        int offset=1;


        if((ret=db_create(&dbp,NULL,0))!=0){
                fprintf(stderr,"db_create: %s\n",db_strerror(ret));
                exit(1);
        }
        dbp->set_flags(dbp,DB_DUP);

        if((ret=dbp->open(dbp,NULL,DATABASE,NULL,DB_BTREE,DB_CREATE,0644))!=0){
                dbp->err(dbp,ret,"%s",DATABASE);
        }
        memset(&key,0,sizeof(key));
        memset(&data,0,sizeof(data));


        //printf("%s\n",geoname);
        for(i=0;geoname[i]!=0;i++){
                if(i%3==0&&i!=0){
                        //printf(":%c%c",geoname[i-3],geoname[i-2]);
                        sprintf(keybuffer,"%c%c",geoname[i-3],geoname[i-2]);
        //                printf(" geooffset: %d - %d\n",geooffset[offset-1],geooffset[offset]);
                        for(d=geooffset[offset-1];d<geooffset[offset];d++){
                                printf("%s\n",geodata[d]);
                                printf("geokey: %s-%s\n",keybuffer,geodata[d]);
                                key.data=keybuffer;
                                key.size=sizeof(keybuffer);
                                data.data=geodata[d];
                                data.size=sizeof(geodata[d]);
                                if((ret=dbp->put(dbp,NULL,&key,&data,0))==0){
                                        printf("DB: %s: key stored\n",(char*)key.data);
                                } else {
                                        printf("key error!\n");
                                }

                        }
                        offset++;
                }
        }
        dbp->close(dbp,0);
        return(0);
}

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <db.h>

#define DATABASE "geo.db"

int main(int argv,char **argc){
        DBT key,data;
        DBC *dbcp;
        DB *dbp;
        int ret;

        if((ret=db_create(&dbp,NULL,0))!=0){
                fprintf(stderr,"db_create: %s\n",db_strerror(ret));
                exit(1);
        }
        dbp->set_flags(dbp,DB_DUP); // we set that so that we can store multiple keys!
        if((ret = dbp->open(dbp,NULL,DATABASE,NULL,DB_BTREE,DB_CREATE,0644))!=0){
                dbp->err(dbp,ret,"%s",DATABASE);
        }
        memset(&key,0,sizeof(key));
        memset(&data,0,sizeof(data));
        /*
        key.data="AT";
        key.size=sizeof("AT");
        data.data="VIE";
        data.size=sizeof("VIE");
*/
       // switch(ret=dbp->put(dbp,NULL,&key,&data,DB_NOOVERWRITE)){
        /*switch(ret=dbp->put(dbp,NULL,&key,&data,0)){
                case 0: printf("db: %s: key stored.\n",(char*)key.data);
                        break;
                case DB_KEYEXIST:
                        printf("db: %s: key previously stored.\n",(char*)key.data);
                        break;
                default:
                        dbp->err(dbp,ret,"DB->put");
        }*/

/*        if((ret=dbp->get(dbp,NULL,&key,&data,0))==0){
                //printf("db: %s: key retrieved: data was %s\n",(char*)key.data,(char*)data.data); 
        } else {
                dbp->err(dbp,ret,"DB->get");
        }*/
        if((ret=dbp->cursor(dbp,NULL,&dbcp,0))!=0){
                dbp->err(dbp,ret,"DB->cursor");
                return(1);
        }
        while((ret=dbcp->c_get(dbcp,&key,&data,DB_NEXT))==0){
                printf("%s\n",(char*)data.data);
/*                if(ret!=DB_NOTFOUND){
                        dbp->err(dbp,ret,"DBcursor->get");
                } */
        }
        dbcp->c_close(dbcp);
        dbp->close(dbp,0);

        return(0);
}

Timing (countrycodes + airportlists) resolving all american airport IATA codes 1000 times

Using hardcoded arrays:

retrieved: 1931000

real    0m0.035s
user    0m0.022s
sys     0m0.002s

Using Sleepycat DB(Btree access):
retrieved: 1931000

real    0m8.211s
user    0m7.377s
sys     0m0.202s