C++通过OCCI操作Oracle数据库详解

1.安装OCCI

如果oracle数据库默认没有安装OCCI，可以自己从官网上下载与自己数据库版本一致的API，地址：http://www.oracle.com/technetwork/topics/linuxsoft-082809.html ； 其中包含四个软件包：

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安装完成之后，会在/usr/lib下多个oracle 共享库文件夹，在/usr/include下多个oracle 头文件（接口）文件夹（可以将他们放到环境变量中）。我的数据库版本是10.2.0，下面以此为例。

2.编写HelloWorld程序测试连接

#include <iostream>
#define LINUXOCCI //避免函数重定义错误
#include <occi.h>
using namespace std;
using namespace oracle::occi;
int main()
{
Environment *env=Environment::createEnvironment(Environment::DEFAULT);
cout<<"success"<<endl;
string name = "scott";
string pass = "tiger";
string srvName = "127.0.0.1:1522/orcl";
try
{
Connection *conn = env->createConnection(name, pass);
cout<<"conn success"<<endl;
env->terminateConnection(conn);
}
catch(SQLException e)
{
cout<<e.what()<<endl;
return -1;
}
Environment::terminateEnvironment(env);
cout<<"end!"<<endl;
return 0;
}

编译命令：

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我没有将occi的路径加入到环境变量中，所以此处要显示列出目录才能通过编译，找到共享库。

运行./test会报错，libocci.so找不到，解决办法很简单：将/usr/lib/oracle/.../lib下的库加入到LD_LIBRARY_PATH中就可以了。

输出结果：

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注：这件不幸的事情可能只发生在我身上了，本人系统中有三个用户，其中一个是oracle，而程序是用另一个用户写的，于是编译通过了，但是运行总是报错：

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后来查明，这个是由于没有设置并导出ORACLE_SID。换了oracle用户试试，居然运行通过了,真的很伤心，原来那个用户没有设置Oracle环境变脸怎么能直接本地访问呢。

3.进行一些操作，执行sql语句

Employees.h

/*
* A simple OCCI test application
* This file contains the Employees class declaration
*/

#include <iostream>
#include <occi.h>
#include <iomanip>

using namespace oracle::occi;
using namespace std;

class Employees {
public:
Employees();
virtual ~Employees();

void List();

private:
Environment *env;
Connection  *con;

string user;
string passwd;
string db;
};

Employees::Employees()
{
/*
69    * connect to the test database as the HR
70    * sample user and use the EZCONNECT method
71    * of specifying the connect string. Be sure
72    * to adjust for your environment! The format
73    * of the string is host:port/service_name
74 */

user = "scott";
passwd = "tiger";
db = "127.0.0.1:1522/orcl";

env = Environment::createEnvironment(Environment::DEFAULT);

try
{
con = env->createConnection(user, passwd, db);
}
catch (SQLException& ex)
{
cout << ex.getMessage();

exit(EXIT_FAILURE);
}
}

Employees::~Employees()
{
env->terminateConnection (con);

Environment::terminateEnvironment (env);
}

void Employees::List()
{
/*
104    * simple test method to select data from
105    * the employees table and display the results
106 */

Statement *stmt = NULL;
ResultSet *rs = NULL;
string sql = "select EMPNO, ENAME, JOB " \
"from EMP order by EMPNO";

try
{
stmt = con->createStatement(sql);
}
catch (SQLException& ex)
{
cout << ex.getMessage();
}

if (stmt)
{
try
{
stmt->setPrefetchRowCount(32);

rs = stmt->executeQuery();
}
catch (SQLException& ex)
{
cout << ex.getMessage();
}

if (rs)
{
cout << endl << setw(8) << left << "EMPNO"
<< setw(22) << left << "ENAME"
<< setw(27) << left << "JOB"
<< endl;
cout << setw(8) << left << "======"
<< setw(22) << left << "===================="
<< setw(27) << left << "========================="
<< endl;

while (rs->next()) {
cout << setw(8) << left << rs->getInt(1)
<< setw(22) << left << (rs->isNull(2) ? "n/a" : rs->getString(2))
<< setw(27) << left << rs->getString(3)
<< endl;
}

cout << endl;
stmt->closeResultSet(rs);
}
con->terminateStatement(stmt);
}
}

main.cc

#include "Employees.h"

using namespace std;
using namespace oracle::occi;

int main (void)
{
/*
48    * create an instance of the Employees class,
49    * invoke the List member, delete the instance,
50    * and prompt to continue...
51 */

Employees *pEmployees = new Employees();

pEmployees->List();

delete pEmployees;

cout << "ENTER to continue...";

cin.get();

return 0;
}

运行结果就不说了，反正是oracle里自带的emp表。