mongodb的C的API使用

MongoDB官方手册：http://docs.mongodb.org/ecosystem/drivers/c/

下载mongodb C driver

[root@slayer ~]# git clone git://github.com/mongodb/mongo-c-driver.git

编译，安装

#cd mongo-c-driver
#make && make install

从官方手册找个demo mongo_c.c

#include <stdio.h>
#include <mongo.h>

int main()
{
mongo conn[1];
int status = mongo_client( conn, "127.0.0.1", 27017 );

if( status != MONGO_OK ) {
switch ( conn->err ) {
case MONGO_CONN_NO_SOCKET:
printf( "no socket\n" );
return 1;
case MONGO_CONN_FAIL:
printf( "connection failed\n" );
return 1;
case MONGO_CONN_NOT_MASTER:
printf( "not master\n" );
return 1;
}
}
printf( "connection done\n");

mongo_destroy( conn );

return 0;
}

编译，运行

[root@slayer mongo-c-driver]# gcc -lmongoc --std=c99 mongo_c.c -o mongo_c
[root@slayer mongo-c-driver]# ./mongo_c
./mongo_c: error while loading shared libraries: libmongoc.so.0.7: cannot open shar
ed object file: No such file or directory

找不到动态库，找找libmongoc.so.0.7在哪

[root@slayer mongo-c-driver]# find / -name libmongoc.so.0.7
/usr/local/lib/libmongoc.so.0.7

看看ld路径

[root@slayer mongo-c-driver]# cat /etc/ld.so.conf
include ld.so.conf.d/*.conf
[root@slayer mongo-c-driver]# cat /etc/ld.so.conf.d/*
/usr/lib64/mysql
/usr/lib/xulrunner-2
/usr/lib64/xulrunner-2

果然没有/usr/local/lib，把它加上试试

[root@slayer mongo-c-driver]# echo /usr/local/lib/ > /etc/ld.so.conf.d/mongoc.conf
[root@slayer mongo-c-driver]# ldconfig
[root@slayer mongo-c-driver]# !gcc
gcc -lmongoc --std=c99 mongo_c.c -o mongo_c
[root@slayer mongo-c-driver]# ./mongo_c
connection done
[root@slayer mongo-c-driver]#

连接成功

简单插入和查询 mongo_c_wr.c

#include <stdlib.h>
#include <stdio.h>
#include <mongo.h>

static void tutorial_insert_batch( mongo *conn ) {
bson *p, **ps;
char *names[4];
int ages[] = { 29, 24, 24, 32 };
int i, n = 4;
names[0] = "Eliot"; names[1] = "Mike"; names[2] = "Mathias"; names[3] = "Richard";

ps = ( bson ** )malloc( sizeof( bson * ) * n);

for ( i = 0; i < n; i++ ) {
p = ( bson * )malloc( sizeof( bson ) );
bson_init( p );
bson_append_new_oid( p, "_id" );
bson_append_string( p, "name", names[i] );
bson_append_int( p, "age", ages[i] );
bson_finish( p );
ps[i] = p;
}

mongo_insert_batch( conn, "mydb.fc", ps, n, NULL, 0 );

for ( i = 0; i < n; i++ ) {
bson_destroy( ps[i] );
free( ps[i] );
}
}

/*
* ===  FUNCTION  ======================================================================
*         Name:  main
*  Description:
* =====================================================================================
*/
int
main ( int argc, char *argv[] )
{
mongo conn[1];
int status = mongo_client( conn, "127.0.0.1", 27017 );

if( status != MONGO_OK ) {
switch ( conn->err ) {
case MONGO_CONN_NO_SOCKET:  printf( "no socket\n" ); return 1;
case MONGO_CONN_FAIL:       printf( "connection failed\n" ); return 1;
case MONGO_CONN_NOT_MASTER: printf( "not master\n" ); return 1;
}
}
printf( "connection done\n" );

/* make bson object */
bson *b = (bson*) malloc(sizeof(bson));
bson_init( b );
bson_append_string( b, "name", "Joe" );
bson_append_int( b, "age", 33);
bson_finish( b );

bson_print(b);

/* insert bson object */
mongo_insert( conn, "mydb.fc", b, NULL);

/* destroy Joe */
bson_destroy( b );
free(b);

/* batch insert */
tutorial_insert_batch(conn);

/* query */
bson query[1];
mongo_cursor  cursor[1];
mongo_cursor_init( cursor, conn, "mydb.fc" );

/* query from database */
while (mongo_cursor_next(cursor) == MONGO_OK)
bson_print(&cursor->current);

mongo_cursor_destroy(cursor);

mongo_destroy( conn );

return EXIT_SUCCESS;

}           /* ----------  end of function main  ---------- */

编译运行

[root@slayer mongo-c-driver]# gcc --std=c99  -lmongoc -lbson mongo_c_wr.c -o mcwr
mongo_c_wr.c: In function 'tutorial_insert_batch':
mongo_c_wr.c:24: warning: passing argument 3 of 'mongo_insert_batch' from incompatible pointer type
[root@postgresql mongo-c-driver]# ./mcwr
connection done
name : 2         Joe
age : 16         33
_id : 7          50c99a05c0ac94782d63d5a1
name : 2         Joe
age : 16         33
_id : 7          50c99a05c8730a6b00000000
name : 2         Eliot
age : 16         29
_id : 7          50c99a05c8730a6b00000001
name : 2         Mike
age : 16         24
_id : 7          50c99a05c8730a6b00000002
name : 2         Mathias
age : 16         24
_id : 7          50c99a05c8730a6b00000003
name : 2         Richard
age : 16         32