在嵌入式Linux上实现BerkeleyDB数据库

在嵌入式Linux上实现BerkeleyDB数据库

Author: misty([e-mail])

Berkeley DB原是Sleepycat软件公司的产品，现被Oracle收购。Berkeley DB使用简单的接口来完成所有数据库的操作，而不是使用SQL语言。

1.1        下载及安装

到Oracle网站上下载版本db-4.4.20.NC.tar.gz，解压后，到目录build-unix下，运行

#../dist/configure –prefix=/home/qibing/opt

#make

#make install

则库文件和头文件安装在目录/home/qibing/opt下，要完全删除运行 #make realclean即可。

1.2        实现及验证

建立文件berkeley.c，并使用下面命令编译

#gcc –I/home/qibing/opt/inclue –L/home/qibing/opt/lib –o Berkeley Berkeley.c –ldb-4.4

 

Berkeley.c

#include

#include

#include

#include

//only this head should include for use bdb.

#include  

#define DATABASE "demo.db"

 

int main()

{

    DB_ENV *myEnv;

    DB *dbp;

    DBT key, data;

    int ret,t_ret;

    u_int32_t env_flags;

    //........... Create an environment object and initialize it for error reporting

    ret = db_env_create(&myEnv, 0);

    if (ret != 0)

    {

          fprintf(stderr, "Error creating env handle: %s\n", db_strerror(ret));

          return -1;

    }

    //........If the environment does not exist create it. Initialize the in-memory cache.

    env_flags = DB_CREATE | DB_INIT_MPOOL;

    //........Open the environment.

    ret = myEnv->open(myEnv,"/home/yangbin1/yangjian/my/db/testevn",env_flags,0);

    if (ret != 0)

    {

          fprintf(stderr, "Environment open failed: %s", db_strerror(ret));

          return -1;

    }

 

    if ((ret = db_create(&dbp, myEnv, 0)) != 0)

    {

          fprintf(stderr, "db_create: %s\n", db_strerror(ret));

          exit (1);

    }

 

    if ((ret = dbp->open(dbp, NULL, DATABASE, NULL, DB_BTREE, DB_CREATE, 0664)) != 0)

    {

          dbp->err(dbp, ret, "%s", DATABASE);

          exit (1);

    }

    memset(&key, 0, sizeof(key));

    memset(&data, 0, sizeof(data)); key.data = "sport";

    key.size = sizeof("sport");

    data.data = "football";

    data.size = sizeof("football");

/*

    //......put data

    if ((ret = dbp->put(dbp, NULL, &key, &data, 0)) == 0)

    {

          printf("db: %s: key stored.\n", (char *)key.data);

    }

      else

    {

          dbp->err(dbp, ret, "DB->put");

    }

*/

 

    //........put data NOOVERWRITE

    if ((ret = dbp->put(dbp, NULL, &key, &data, DB_NOOVERWRITE)) == 0)

    printf("db: %s: key stored.\n", (char *)key.data);

    else dbp->err(dbp, ret, "DB->put");

 

    //.......get data

    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");

 

    //......del data

    if((ret = dbp->del(dbp, NULL, &key, 0)) == 0)

    printf("db: %s: key was deleted.\n", (char *)key.data);

    else

    dbp->err(dbp, ret, "DB->del");

 

    //.........close, only when the db successful closed,the data can real write to the disk.

    //if ((t_ret = dbp->close(dbp, 0)) != 0 && ret == 0)

    //ret = t_ret;

    //exit(ret);

    if (dbp != NULL)

    dbp->close(dbp, 0);

    //.........close evn

    //........When you are done with an environment, you must close it.

    //........Before you close an environment, make sure you close any opened databases

    if (myEnv != NULL)

    myEnv->close(myEnv, 0);

 

    return 0;

}

End of Berkeley.c

编译好后，运行./berkeley即可。 附件为本文中的代码（这个代码我未具体验证）

文件:	berkeley.rar
大小:	1KB
下载:	下载

参考：http://www.cnblogs.com/huqingyu/archive/2006/10/06/522251.html

在嵌入式上实现时，用交叉编译gcc编译并把库放在目标板上。