postgres数据库开发笔记

PostgreSQL连接C/C++接口实例

http://www.yiibai.com/html/postgresql/2013/080894.html

库使用介绍，常用SQL语句，提供库使用示例，使用c/c++ 访问 postgres 数据库，使用 SQL标准语句是一个不错的选择。

本文记录一个资料链接，以备后用。 先看上面链接中的介绍和各个语句的使用方法，下面的工程，linux上和windows上环境搭建好了之后，可以直接使用。

wget http://pqxx.org/download/software/libpqxx/libpqxx-4.0.tar.gz tar xvfz libpqxx-4.0.tar.gz
cd libpqxx-4.0
./configure
make
make install yiib

示例测试代码：

#include <iostream>
#include <pqxx/pqxx>
#include <stdio.h>
#include <stdlib.h>

using namespace std;
using namespace pqxx;

#include <iostream>
#include <pqxx/pqxx>

using namespace std;
using namespace pqxx;

int main(int argc, char* argv[])
{
char * sql;

try{
connection C("dbname=streamMediaDataBase user=postgres password=cdzchx \
hostaddr=127.0.0.1 port=5432");
if (C.is_open()) {
cout << "Opened database successfully: " << C.dbname() << endl;
} else {
cout << "Can't open database" << endl;
return 1;
}
/* Create SQL statement */

//      sql =
//      "INSERT INTO STREAM_MEDIA_INFO (CHANNEL,RTSPURL,RTMPURL,PUSHPID,TIPS,SRCALIVE) VALUES (6, 'rtsp://1111', 'rtmp://1111', 1111, 'notips',true ) \
//      ,(7, 'rtsp://1111', 'rtmp://1111', 1111, 'notips',true )\
//      ,(8, 'rtsp://1111', 'rtmp://1111', 1111, 'notips',true )\
//      ,(9, 'rtsp://1111', 'rtmp://1111', 1111, 'notips',true )\
//    		  ";

//      sql =(char*)
//          "SELECT * FROM STREAM_MEDIA_INFO WHERE\
//          channel>0\
//        		  ";
//

sql =(char*)
"UPDATE STREAM_MEDIA_INFO SET rtmpurl='rtmp://woshiceshi'  WHERE\
channel=0\
";

/* Create a transactional object. */
work W(C);

/* Execute SQL query */
pqxx::result ret  = W.exec( sql );
W.commit();

for (pqxx::result::const_iterator row = ret.begin(); row != ret.end(); ++row)
{

for (pqxx::tuple::const_iterator field = row->begin();field != row->end();++field)
{
printf(" %s: %s \n", field.name() ,field->c_str() );

}
std::cout << std::endl;
}

C.disconnect ();

}catch (const std::exception &e){
cerr << e.what() << std::endl;
return 1;
}

return 0;
}

封装后的代码：

cpp文件：

#include <PostGres.h>

postGresConnector_c::postGresConnector_c(const char* dbname_,const char* usr_,const char* passwd_,
const char* hostaddr_,const char* port_,list<string> table_list_)
:m_dbConnection(NULL),m_dbWork (NULL)
{
this->InitialPostGresConnector( dbname_, usr_, passwd_, hostaddr_, port_,table_list_);
this->ConnectDB();
}
postGresConnector_c::~postGresConnector_c()
{

}
void postGresConnector_c::InitialPostGresConnector(const char* dbname_,const char* usr_,const char* passwd_,
const char* hostaddr_,const char* port_,list<string> table_list_)
{
assert( dbname_!=NULL && usr_!=NULL && passwd_!=NULL && hostaddr_!=NULL && port_!=NULL);

strcpy(m_postGresConnectorInfo.dbname,dbname_);
strcpy(m_postGresConnectorInfo.hostaddr,hostaddr_);
strcpy(m_postGresConnectorInfo.passwd,passwd_);
strcpy(m_postGresConnectorInfo.port,port_);
strcpy(m_postGresConnectorInfo.usr,usr_);

m_postGresConnectorInfo.table_list = table_list_ ;

}
bool postGresConnector_c::ConnectDB()
{
try{
char CMD[2048];
sprintf(CMD,"dbname=%s user=%s password=%s hostaddr=%s port=%s",
m_postGresConnectorInfo.dbname,
m_postGresConnectorInfo.usr,
m_postGresConnectorInfo.passwd,
m_postGresConnectorInfo.hostaddr,
m_postGresConnectorInfo.port);
m_dbConnection = new connection(CMD);

if (m_dbConnection->is_open()) {
cout << "Opened database successfully: " << m_dbConnection->dbname() << endl;
return false ;
} else {
cout << "Can't open database" << endl;
return true;
}

}catch (const std::exception &e){
cerr << e.what() << std::endl;
return 1;
}
}
void postGresConnector_c::Disconnect()
{
if(m_dbConnection!=NULL)
m_dbConnection->disconnect ();
}
void postGresConnector_c::DoSQL_SQLSentence(const char* sentence_)
{
try{
if(!m_dbConnection)
return ;
/* Create a transactional object. */
work W(*m_dbConnection);

/* Execute SQL query */
W.exec( sentence_ );
W.commit();

}catch (const std::exception &e){
Fprint_String(e.what(),"StdError","a+");
cerr << e.what() << std::endl;
}
}
pqxx::result postGresConnector_c::DoSQL_SELECTALL(const char* tableName_)
{
try{
char sql[1024] ;
sprintf(sql,"SELECT * FROM %s ",tableName_);

/* Create a transactional object. */
work W(*m_dbConnection);

/* Execute SQL query */
pqxx::result ret = W.exec( sql );
W.commit();

for (pqxx::result::const_iterator row = ret.begin(); row != ret.end(); ++row)
{

for (pqxx::tuple::const_iterator field = row->begin();field != row->end();++field)
{
printf(" %s: %s \n", field.name() ,field->c_str() );

}
std::cout << std::endl;
}
return ret ;
}catch (const std::exception &e){
Fprint_String(e.what(),"StdError","a+");
cerr << e.what() << std::endl;
}
}

int main_post()
{
char SQLSentence[2048];
printf("Test dbConnector \n");

list<string> tableList ;
tableList.push_front("stream_media_info");
tableList.push_front("stream_media_info2");
tableList.push_front("stream_media_info3");

postGresConnector_c tmpPostGresConnector("streamMediaDataBase","postgres","cdzchx","127.0.0.1","5432",tableList);
// tmpPostGresConnector.DoSQL_SELECTALL("stream_media_info");

tableList.pop_back();
tableList.pop_back();

tmpPostGresConnector.ShowTableList();
/*
* INSERT INTO __ (__,__,__) VALUES (__,__,__),(__,__,__)
* DELETE FROM __ WHERE __=__
* SELECT * FROM __
* UPDATE __ SET __=__
* */
// sprintf(SQLSentence,"INSERT INTO STREAM_MEDIA_INFO (CHANNEL,RTSP_URL,RTMP_URL,PUSH_PID,TIPS,SRC_ALIVE)\
// VALUES (10,'rtsp://woshi:rrtt','rtmp://woshirtttmmmppp',1234,'want tips?',true),\
// (11,'rtsp://woshi:rrtt','rtmp://woshirtttmmmppp',1234,'want tips?',true)\
// \
// ");
// sprintf(SQLSentence,"DELETE FROM STREAM_MEDIA_INFO WHERE channel=11\
// \
// \
// \
// ");
sprintf(SQLSentence,"UPDATE STREAM_MEDIA_INFO SET rtmp_url='rtmp://wolaishishirtmpceshi!' WHERE channel=11\
\
\
\
");
tmpPostGresConnector.DoSQL_SQLSentence(SQLSentence);
}


头文件：
#ifndef POSTGRES_H_
#define POSTGRES_H_

#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <pqxx/pqxx>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <string>

using namespace std;
using namespace pqxx;

#include <iostream>
#include <pqxx/pqxx>
#include <list>

#include <systemfun.h>

using namespace std;
using namespace pqxx;

typedef struct
{
char dbname[1024];
char usr[1024];
char passwd[1024];
char hostaddr[1024];
char port[1024];
list<string> table_list ;

}postGresConnectorInfo;

/*
* INSERT INTO __ (__,__,__) VALUES (__,__,__),(__,__,__)
* DELETE FROM __ WHERE __=__
* SELECT * FROM __
* UPDATE __ SET __=__
* */

class postGresConnector_c
{
public:
postGresConnector_c(const char* dbname_,const char* usr_,const char* passwd_,
const char* hostaddr_,const char* port_,list<string> table_list_) ;
~postGresConnector_c();

list<string>* GetAttribute_tablelist(){return &m_postGresConnectorInfo.table_list ;}
char* GetAttribute_dbname(){return m_postGresConnectorInfo.dbname;}
char* GetAttribute_usr(){return m_postGresConnectorInfo.usr;}
char* GetAttribute_passwd(){return m_postGresConnectorInfo.passwd;}
char* GetAttribute_hostaddr(){return m_postGresConnectorInfo.hostaddr;}
char* GetAttribute_port(){return m_postGresConnectorInfo.port;}

void PushFrontTableList(string tableList_){m_postGresConnectorInfo.table_list.push_front(tableList_);}
void PopBackTableList(){m_postGresConnectorInfo.table_list.pop_back();}
void ShowTableList(){
list<string>::iterator iter;
for(iter=m_postGresConnectorInfo.table_list.begin();iter!=m_postGresConnectorInfo.table_list.end();++iter){
printf("%s\n",iter->c_str());
}
}

pqxx::result DoSQL_SELECTALL(const char* tableName_);
void DoSQL_SQLSentence(const char* sentence_) ;

private:
void InitialPostGresConnector(const char* dbname_,const char* usr_,const char* passwd_,
const char* hostaddr_,const char* port_,list<string> table_list_);
bool ConnectDB();
void Disconnect() ;
private:
postGresConnectorInfo m_postGresConnectorInfo ;
connection *m_dbConnection ;
work *m_dbWork ;
};

#endif /* POSTGRES_H_ */