Nosql数据库之mongodb c++使用实例

mongodb是一个非关系型高速数据库，由多个文档（相当于关系数据库中的行记录）组成集合，多个集合（相当于关系数据库中的数据表）组成数据库。

使用命令安装或者源码安装mongodb，安装完成后mongod就是mongodb数据库服务的主程序了，指定参数或者配置文件启动命令如下

mongod -f /etc/mongodb.conf

或者

mongod --dbpath=/home/lsx/mdata

启动成功后可以在控制台看见一些ip和端口，数据存储目录的信息如下：

配置文件里面有ip，端口，数据存储目录的信息：

# mongodb.conf

# Where to store the data.
dbpath=/var/lib/mongodb

#where to log
logpath=/var/log/mongodb/mongodb.log

logappend=true

bind_ip = 127.0.0.1
#port = 27017

# Enable journaling, http://www.mongodb.org/display/DOCS/Journaling
journal=true

# Enables periodic logging of CPU utilization and I/O wait
#cpu = true

# Turn on/off security.  Off is currently the default
#noauth = true
#auth = true

# Verbose logging output.
#verbose = true

# Inspect all client data for validity on receipt (useful for
# developing drivers)
#objcheck = true

# Enable db quota management
#quota = true

# Set oplogging level where n is
#   0=off (default)
#   1=W
#   2=R
#   3=both
#   7=W+some reads
#oplog = 0

# Diagnostic/debugging option
#nocursors = true

# Ignore query hints
#nohints = true

# Disable the HTTP interface (Defaults to localhost:27018).
#nohttpinterface = true

# Turns off server-side scripting.  This will result in greatly limited
# functionality
#noscripting = true

# Turns off table scans.  Any query that would do a table scan fails.
#notablescan = true

# Disable data file preallocation.
#noprealloc = true

# Specify .ns file size for new databases.
# nssize = 

# Accout token for Mongo monitoring server.
#mms-token = 

# Server name for Mongo monitoring server.
#mms-name = 

# Ping interval for Mongo monitoring server.
#mms-interval = 

# Replication Options

# in replicated mongo databases, specify here whether this is a slave or master
#slave = true
#source = master.example.com
# Slave only: specify a single database to replicate
#only = master.example.com
# or
#master = true
#source = slave.example.com

# Address of a server to pair with.
#pairwith = 
# Address of arbiter server.
#arbiter = 
# Automatically resync if slave data is stale
#autoresync
# Custom size for replication operation log.
#oplogSize = 
# Size limit for in-memory storage of op ids.
#opIdMem = 

# SSL options
# Enable SSL on normal ports
#sslOnNormalPorts = true
# SSL Key file and password
#sslPEMKeyFile = /etc/ssl/mongodb.pem
#sslPEMKeyPassword = pass

下载一个mongodb的c语言开发驱动包mongo-c-driver-1.3.5，写一个测试程序，插入一个文档

/* gcc example.c -o example $(pkg-config --cflags --libs libmongoc-1.0) */

/* ./example-client [CONNECTION_STRING [COLLECTION_NAME]] */

#include 
#include 
#include 
#include 

#include "bson-types.h"
int main (int argc, char *argv[])
{
   mongoc_client_t *client;
   mongoc_collection_t *collection;
   mongoc_cursor_t *cursor;
   bson_error_t error;
   const bson_t *doc;
   const char *uristr = "mongodb://192.168.2.41/";
   const char *collection_name = "my_coll";
   bson_t query;
   char *str;

   mongoc_init ();

   if (argc > 1) {
      uristr = argv [1];
   }

   if (argc > 2) {
      collection_name = argv [2];
   }

   client = mongoc_client_new (uristr);

   if (!client) {
      fprintf (stderr, "Failed to parse URI.\n");
      return EXIT_FAILURE;
   }

   bson_init (&query);

#if 0
   bson_append_utf8 (&query, "hello", -1, "world", -1);
#endif

   collection = mongoc_client_get_collection (client, "hfrz", collection_name);
   /
   bson_t *doc2 = bson_new();
   BSON_APPEND_INT64(doc2, "id", 1);
   BSON_APPEND_INT64(doc2, "field1", 0);
   const char *msg = "test message";
   BSON_APPEND_BINARY(doc2, "field2", BSON_SUBTYPE_BINARY, (const uint8_t*)(msg), (uint32_t)(strlen(msg)+1));
   BSON_APPEND_UTF8 (doc2, "hello", "world");
   bool r = mongoc_collection_insert(collection, MONGOC_INSERT_NONE, doc2, NULL, &error);
   if (!r)
       printf("Insert Failure:%s\n", error.message);
   /

   cursor = mongoc_collection_find (collection,
                                    MONGOC_QUERY_NONE,
                                    0,
                                    0,
                                    0,
                                    &query,
                                    NULL,  /* Fields, NULL for all. */
                                    NULL); /* Read Prefs, NULL for default */

   while (mongoc_cursor_next (cursor, &doc)) {
      str = bson_as_json (doc, NULL);
      fprintf (stdout, "%s\n", str);
      bson_free (str);
   }

   if (mongoc_cursor_error (cursor, &error)) {
      fprintf (stderr, "Cursor Failure: %s\n", error.message);
      return EXIT_FAILURE;
   }

   bson_destroy (&query);
   mongoc_cursor_destroy (cursor);
   mongoc_collection_destroy (collection);
   mongoc_client_destroy (client);

   mongoc_cleanup ();

   return EXIT_SUCCESS;
}

example:example-client.c
	g++ example-client.c -o example -g -I/usr/local/include/libmongoc-1.0 -I/usr/local/include/libbson-1.0 -L/usr/local/lib -lmongoc-1.0 -lbson-1.0
#$(pkg-config --cflags --libs libmongoc-1.0)
clean:
	rm -f example

mongodb有很多的可视化工具，使用nosql manager for mongodb就可以在界面上看见刚才插入的文档了，如下图：