封装connect/c++连接mysql

参考前一篇文章

参考网址：http://dev.mysql.com/tech-resources/articles/mysql-connector-cpp.html#trx

头文件：

#include <iostream>
#include <stdio.h>
#include "mysql_connection.h"
#include "mysql_driver.h"
#include "mysql_error.h"
#include "cppconn/connection.h"
#include "cppconn/statement.h"
#include "cppconn/resultset.h"
#include "cppconn/metadata.h"
#include "cppconn/prepared_statement.h"
#include "cppconn/parameter_metadata.h"
#include "cppconn/sqlstring.h"
#include <string>

#define DBHOST "tcp://127.0.0.1:3306"
#define USER "root"
#define PASSWORD "root"
#define DATABASE "test"

using namespace std;
using namespace sql;
using namespace sql::mysql;

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

	bool Connect();
	bool IsAliveConn();
	bool IsCloseConn();
	void Execute(const SQLString& sql);
	bool ExecuteQuery(const SQLString& sql);
	void ExecuteUpdate(const SQLString& sql);
	bool ExecuteProcedure(const SQLString& sql);
	void RollBack(Savepoint * savepoint=NULL);
	void Commit();

	int getColumnCount();
	int getRowCount();
	string getColumnName(int index);
	void PrintDataBaseInfo();

	bool isValueNull(int columnindex);
	bool isValueNull(const string& columnname);
	bool ReConnect();
	void SetTable(const string& tablename);
	int getValueInt(const string& columnname);
	string getValueString(const string& columnname);
	bool getNext();
	
private:
	mysql::MySQL_Driver *driver;
	Connection *conn;
	Statement *state;
	ResultSet *res;
	DatabaseMetaData  *dbcon_meta;
	ResultSetMetaData *rs_meta;
	sql::PreparedStatement *prep_stmt;
	Savepoint *savept;
};

源文件：

#include "mysql_c++.h"

MysqlOperation::MysqlOperation()
{
	if(!Connect())
	{
		cout << "create the mysqloperation obj err\n";
		return;
	}
	//turn off the autocommit
	conn->setAutoCommit(0);
	conn->setSchema(DATABASE);
	cout << "connet to database OK\n"; 
}

MysqlOperation::~MysqlOperation()
{
	if(res)
	{
		delete res;
		res = NULL;
	}
	if(state)
	{
		delete state;
		state = NULL;
	}
	if(prep_stmt)
	{
		delete prep_stmt;
		prep_stmt = NULL;
	}
	if(conn)
	{
		conn->close();
		delete conn;
		conn = NULL;
	}
}

void MysqlOperation::SetTable(const string& tablename)
{
	conn->setSchema(tablename);
}

bool MysqlOperation::Connect()
{
	
	driver = mysql::get_driver_instance();
	if(driver == NULL)
	{
		cout << "get driver err\n";
		return false;
	}
	conn = driver->connect(DBHOST, USER, PASSWORD);
	state = conn->createStatement();
	if(!conn || !state)
		return false;
	return true;
}

bool MysqlOperation::IsAliveConn()
{
	return conn->isValid()?true:false;
}

bool MysqlOperation::IsCloseConn()
{
	return conn->isClosed()?true:false;
}

int MysqlOperation::getColumnCount()
{
	if(res == NULL)
	{
    	return -1;
	}
	rs_meta = res->getMetaData();
	int cols = rs_meta->getColumnCount();
	return cols;
}

int MysqlOperation::getRowCount()
{
	int rows = 0;
	rows = res->rowsCount();
	return rows;
}

void MysqlOperation::Execute(const SQLString& sql)
{
	if(!state)
	{
		state = conn->createStatement();
	}
	state->execute(sql);
}

bool MysqlOperation::ExecuteProcedure(const SQLString& sql)
{
	
}

void MysqlOperation::PrintDataBaseInfo()
{
	if(dbcon_meta == NULL)
	{
		dbcon_meta = conn->getMetaData();	
	}	
	cout << "Database Product Name: " << dbcon_meta->getDatabaseProductName() << endl;  
    cout << "Database Product Version: " << dbcon_meta->getDatabaseProductVersion() << endl;  
    cout << "Database User Name: " << dbcon_meta->getUserName() << endl << endl;  
  
    cout << "Driver name: " << dbcon_meta->getDriverName() << endl;  
    cout << "Driver version: " << dbcon_meta->getDriverVersion() << endl << endl;  
  
    cout << "Database in Read-Only Mode?: " << dbcon_meta->isReadOnly() << endl;  
    cout << "Supports Transactions?: " << dbcon_meta->supportsTransactions() << endl;  
    cout << "Supports DML Transactions only?: " << dbcon_meta->supportsDataManipulationTransactionsOnly() << endl;  
    cout << "Supports Batch Updates?: " << dbcon_meta->supportsBatchUpdates() << endl;  
    cout << "Supports Outer Joins?: " << dbcon_meta->supportsOuterJoins() << endl;  
    cout << "Supports Multiple Transactions?: " << dbcon_meta->supportsMultipleTransactions() << endl;  
    cout << "Supports Named Parameters?: " << dbcon_meta->supportsNamedParameters() << endl;  
    cout << "Supports Statement Pooling?: " << dbcon_meta->supportsStatementPooling() << endl;  
    cout << "Supports Stored Procedures?: " << dbcon_meta->supportsStoredProcedures() << endl;  
    cout << "Supports Union?: " << dbcon_meta->supportsUnion() << endl << endl;  
  
    cout << "Maximum Connections: " << dbcon_meta->getMaxConnections() << endl;  
    cout << "Maximum Columns per Table: " << dbcon_meta->getMaxColumnsInTable() << endl;  
    cout << "Maximum Columns per Index: " << dbcon_meta->getMaxColumnsInIndex() << endl;  
    cout << "Maximum Row Size per Table: " << dbcon_meta->getMaxRowSize() << " bytes" << endl;  
  
    cout << "/nDatabase schemas: " << endl;  
  
    auto_ptr < ResultSet > rs ( dbcon_meta->getSchemas());  
  
    cout << "/nTotal number of schemas = " << rs->rowsCount() << endl;  
    cout << endl;  
  
}
//execute select sql and return resultset
bool MysqlOperation::ExecuteQuery(const SQLString& sql)
{
	if (!state)
	{
		state = conn->createStatement();
	}
	res = state->executeQuery(sql);
	if(res)
		return true;
	else
		return false;
}

void MysqlOperation::Commit()
{
	conn->commit();
}

void MysqlOperation::RollBack(Savepoint * savepoint)
{
	conn->rollback(savepoint);
	conn->releaseSavepoint(savepoint);	
}

//execute insert,update,delete sql
void MysqlOperation::ExecuteUpdate(const SQLString& sql)
{
	savept = conn->setSavepoint("savept");
	try{
		conn->setTransactionIsolation(TRANSACTION_SERIALIZABLE); //when change the data,we can't read the data
		prep_stmt = conn->prepareStatement(sql);	
		int updatecount = prep_stmt->executeUpdate();
		if(updatecount == 0)
		{
			printf("no rows update\n");
			return;
		}
		Commit();
	}catch(SQLException &e)
	{
		cout << "ERROR: SQLException in " << __FILE__;
		cout << " (" << __func__<< ") on line " << __LINE__ << endl;
		cout << "ERROR: " << e.what();
		cout << " (MySQL error code: " << e.getErrorCode();
		cout << ", SQLState: " << e.getSQLState() << ")" << endl;
		RollBack(savept);
	}	
}

string MysqlOperation::getColumnName(int index)
{
	if(rs_meta == NULL)
	{
		rs_meta = res->getMetaData();
	}
	string columnname = rs_meta->getColumnLabel(index+1);
	return columnname;
}

bool MysqlOperation::isValueNull(int columnindex)
{
	return res->isNull(columnindex)?true:false;
}

bool MysqlOperation::isValueNull(const string& columnname)
{
	return res->isNull(columnname)?true:false;
}

bool MysqlOperation::ReConnect()
{
	return conn->reconnect();
}

int MysqlOperation::getValueInt(const string& columnname)
{
	int value = res->getInt(columnname);
	return value;
}

string MysqlOperation::getValueString(const string& columnname)
{
	string value = res->getString(columnname);
	return value;
}

bool MysqlOperation::getNext()
{
	return res->next();
}

int main(int argc, char *argv[])
{
    MysqlOperation *opera = new MysqlOperation();
	if(!opera->IsAliveConn())
	{
		opera->ReConnect();
	}
	cout << opera->IsAliveConn() << endl;
	opera->SetTable("test");

	opera->PrintDataBaseInfo();

	SQLString sql = "select * from user";
	opera->ExecuteQuery(sql);
	cout << "row num:"<< opera->getRowCount() << " " << "cols num:" << opera->getColumnCount() << endl;

	while(opera->getNext())
	{
		cout << opera->getValueInt("id") << ":" << opera->getValueString("name") << ":" << opera->getValueInt("sex") << ":" << opera->getValueString("password") << endl; 
	}

	SQLString sql2 = "delete from user where name = '@name'";
	sql2.SetParam("@name", "hehe");  //注意：需要修改库文件sqlstring.h
	cout << sql2 << endl;
	opera->ExecuteUpdate(sql2);

	SQLString sql3 = "create table if not exists tt (id int not null auto_increment, name varchar(20) not null, age int, primary key(id))";
	opera->Execute(sql3);
	opera->Execute("drop table tt");
    return 0;
}

修改sqlstring.h，添加

	void SetParam(const char *name, long val)
		{
			char buf[32];
			sprintf(buf, "%ld", val);
			SetParam(name, buf);
		}
		void SetParam(const char *name, long long val)
		{
			char buf[64];
			sprintf(buf, "%lld", val);
			SetParam(name, buf);
		}
		void SetParam(const char *name, double val)
		{
			char buf[32];
			sprintf(buf, "%.8f", val);
			SetParam(name, buf);
		}
		void SetParam(const char *name, const char *val)
		{
			unsigned int pos = 0;
			int len = strlen(name);
			int newlen = strlen(val);
			pos = realStr.find(name);
			while(pos != -1)
			{
				realStr.replace(pos, len, val);
				pos = realStr.find(name, pos+newlen);
			}
		}

编译测试：

g++ -g -o test mysql_c++.h mysql_c++.cpp  -I/home/laijia/database/include -I/home/laijia/database/include/cppconn -I/usr/include -L/home/laijia/database/lib -L/usr/local/lib -lmysqlcppconn -lmysqlcppconn-static