NAME

sdb_init, sdb_open, sdb_query, sdb_close - the Simple Database Library.

SYNOPSIS

#include <sdb.h>

void sdb_init();
char *sdb_open(char *url);
void sdb_close(char *id);
int sdb_query(char *url, char *query, int (*callback)(int, char **, void *), void *closure);

DESCRIPTION

The SDB library allows applications to support multiple database management systems with negligeable overhead, in terms of code as well as system resources.

sdb_init() initializes the library and registers the database drivers. It is not necessary to call sdb_init explicitly, since it will be done automatically when needed.

sdb_open() opens a database connection that can be used for multiple queries. This is optional; calling sdb_query directly will simply open and close the connection for each query. sdb_open returns a connection id which is used in place of the url in calls to sdb_query.

sdb_query() calls the callback once for each row returned. No rows does not indicate an error condition. sdb_query returns the number of rows or -1 for error. The callback takes three arguments, an integer indicating the number of columns in the result, an array of pointers to the fields and a pointer to some arbitrary data that the callback might need. Values are always returned as strings.

sdb_close() closes the database connection opened by sdb_open.

EXAMPLES

This minimal program runs queries from the command line.

#include <stdio.h>
#include <stdlib.h>
#include <sdb.h>
static int callback(int n, char **p, void *closure)
{


    int i;


    for (i = 0; i < n; i++) {


        printf("%s\t", p[i]);


    }


    printf("0);


    return 0;
}
int main(int argc, char **argv)
{


    if (argc != 3) {


        fprintf(stderr, "Usage: sdb_demo url query\n");


        return EXIT_FAILURE;


    }


    sdb_query(argv[1], argv[2], callback, NULL);


    return EXIT_SUCCESS;
}

This program can be used to authenticate Squid proxy users.

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sdb.h>
static int cb_db(int n, char **p, void *closure)
{


    return 0;
}
int main(int argc, char **argv)
{


    char *url, query[1024];


    int n;


    char buf[256];


    char *user, *passwd, *p;


    setbuf(stdout, NULL);


    if (argc != 2) {


        fprintf(stderr, "Usage: sdb_auth url\n");


        exit(1);


    }


    url = argv[1];


    while (fgets(buf, 256, stdin) != NULL) {


        if ((p = strchr(buf, '\n')) != NULL)


            *p = '\0';          /* strip \n */


        if ((user = strtok(buf, " ")) == NULL) {


            printf("ERR\n");


            continue;


        }


        if ((passwd = strtok(NULL, "")) == NULL) {


            printf("ERR\n");


            continue;


        }


        sprintf(query,


                "select * from htpasswd "


                "where user = '%s' "


                "and passwd = '%s'",


                user, passwd);


        n = sdb_query(url, query, cb_db, NULL);


        if (n < 1) {


            printf("ERR\n");


        } else {


            printf("OK\n");


        }


    }


    exit(0);
}

SEE ALSO

sdbd.8

Example clients in sdb_client.c and sdbd_client.c.

AUTHOR

Copyright (c) 2000-2005 Ulric Eriksson <ulric@siag.nu>

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the Licence, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details.

You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.