Linux下g++编译C++连接oracle(OCCI)出现的问题及解决方式
文章分类:C++编程 由于项目原因,开始学习C++,刚接触半个多月,今天参考网上例子,写了个简单的C++连接ORACLE的DEMO,可是使用g++编译时不顺利,不是报这个错就是那个,最后参考网上的解决方式和个人理解,终于调试好了,现把编译中出现的问题和解决方法总结出来。源代码
- #include <iostream>
- #include <string>
- #include "occi.h"
- using namespace oracle::occi;
- using namespace std;
- int main()
- {
- string usr="sys";
- string pwd="orcl";
- string SID="ORCL";
- string date;
- Environment *env=Environment::createEnvironment(Environment::OBJECT);
- Connection *conn= env->createConnection(usr,pwd,SID);//all strings
- if(conn)
- cout<<"success createConnection!"<<endl;
- else
- cout<<"failure createConnection!"<<endl;
- Statement *stmt = conn->createStatement();
- string sSQL = "select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual";
- stmt->setSQL(sSQL);
- ResultSet *rs = stmt->executeQuery();
- if(rs->next())
- {
- date = rs->getString(1);
- }
- cout<<"now time :"<<date<<endl;
- env->terminateConnection(conn);
- Environment::terminateEnvironment(env);
- return 0;
- }
- #include <iostream>
- #include <string>
- #include "occi.h"
- using namespace oracle::occi;
- using namespace std;
- int main()
- {
- string usr="sys";
- string pwd="orcl";
- string SID="ORCL";
- string date;
- Environment *env=Environment::createEnvironment(Environment::OBJECT);
- Connection *conn= env->createConnection(usr,pwd,SID);//all strings
- if(conn)
- cout<<"success createConnection!"<<endl;
- else
- cout<<"failure createConnection!"<<endl;
- Statement *stmt = conn->createStatement();
- string sSQL = "select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual";
- stmt->setSQL(sSQL);
- ResultSet *rs = stmt->executeQuery();
- if(rs->next())
- {
- date = rs->getString(1);
- }
- cout<<"now time :"<<date<<endl;
- env->terminateConnection(conn);
- Environment::terminateEnvironment(env);
- return 0;
- }
本人linux上安装oracle路径:/opt/app/oracle/product/10.2.0/db_1
编译命令:g++ -o conn -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -g
问题一:编译时报如下错误:
- [oracle@localhost demo]$ g++ g++ -o conn -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib -lclntsh -locci /usr/lib/libstdc++.so.5 conn_db.cpp -g
- g++: g++: No such file or directory
- conn_db.cpp:3:18: error: occi.h: No such file or directory
- conn_db.cpp:4: error: 'oracle' has not been declared
- conn_db.cpp:4: error: 'occi' is not a namespace-name
- conn_db.cpp:4: error: expected namespace-name before ';' token
- conn_db.cpp: In function 'int main()':
- conn_db.cpp:14: error: 'Environment' was not declared in this scope
- conn_db.cpp:14: error: 'env' was not declared in this scope
- conn_db.cpp:14: error: 'Environment' is not a class or namespace
- conn_db.cpp:14: error: 'Environment' is not a class or namespace
- conn_db.cpp:15: error: 'Connection' was not declared in this scope
- conn_db.cpp:15: error: 'conn' was not declared in this scope
- conn_db.cpp:21: error: 'Statement' was not declared in this scope
- conn_db.cpp:21: error: 'stmt' was not declared in this scope
- conn_db.cpp:26: error: 'ResultSet' was not declared in this scope
- conn_db.cpp:26: error: 'rs' was not declared in this scope
- conn_db.cpp:35: error: 'Environment' is not a class or namespace
解决:编译时没有引入OCCI头文件,如果没有,先下载对应的 ORACLE client安装,比如我的是oracle10g,下载了oracle-instantclient-basic- 10.2.0.4-1.i386.zip,解压到一个目录下(/home/oracle/oracle/include),然后在编译文件的时候引进这个解压目录
编译命令增加OCCI目录:g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -g
问题2:找不到对应函数
- [oracle@localhost demo]$ g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -Wall -O -g
- /tmp/cclFs9xq.o: In function `main':
- /home/oracle/oracle/demo/conn_db.cpp:14: undefined reference to `oracle::occi::Environment::createEnvironment(oracle::occi::Environment::Mode, void*, void* (*)(void*, unsigned int), void* (*)(void*, void*, unsigned int), void (*)(void*, void*))'
- /home/oracle/oracle/demo/conn_db.cpp:35: undefined reference to `oracle::occi::Environment::terminateEnvironment(oracle::occi::Environment*)'
- collect2: ld returned 1 exit status
解决:增加libocci.so和libclntsh.so指定编译
修改后的编译命令: g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -lclntsh -locci -Wall -O -g
另外可能在引入-lclntsh -locci编译时可能会报找不到以下错误:
- [oracle@localhost demo]$ g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -lclntsh -locci /usr/lib/libstdc++.so.5 -Wall -O -g
- /usr/bin/ld: cannot find -lclntsh
- collect2: ld returned 1 exit status
- [oracle@localhost demo]$
解决:这是因为没有找到libclntsh.so和libocci.so链接库,你在可以把oracle client安装目录下把这两个文件拷贝到$ORACLE_HOME/lib目录下,或加到/usr/lib目录下就可以了
问题三:occi在linux编译运行时报libstdc++.so.6冲突的问题
- [oracle@localhost demo]$ g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -lclntsh -locci -Wall -O -g
- /usr/bin/ld: warning: libstdc++.so.5, needed by /opt/app/oracle/product/10.2.0/db_1/lib/libocci.so, may conflict with libstdc++.so.6
- [oracle@localhost demo]$ g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -lclntsh -locci -Wall -O -g
- /usr/bin/ld: warning: libstdc++.so.5, needed by /opt/app/oracle/product/10.2.0/db_1/lib/libocci.so, may conflict with libstdc++.so.6
解决:OCCI库在linux编译的时候,由于linux版本太高,会提示以上情况,实际上,在大多数linux系统上,还保留有libstdc++5的库,自己手工在编译的时候加上去就好了
修改后的编译命令:g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib -lclntsh -locci /usr/lib/libstdc++.so.5 conn_db.cpp -g
编译通过后执行结果输出:
- [oracle@localhost demo]$ g++ -o conn -I/home/oracle/oracle/include -L/opt/app/oracle/product/10.2.0/db_1/lib -L/opt/oracle/product/10.2.0/db_1/rdbms/lib conn_db.cpp -lclntsh -locci /usr/lib/libstdc++.so.5 -Wall -O -g
- [oracle@localhost demo]$ ./conn
- success createConnection!
- now time :2010-11-14 22:49:24
- [oracle@localhost demo]$