数据库MySql类库系列(四)-QueryOperatorSelect

第四个工具类，QueryOperatorSelect

负责处理：直接执行sql方式下的，查找，以及获取查找结果的需求。

用到了之前的DBOperator，主要是封装其ExecQuery接口。

另外提供获取查询结果的相应接口：

从结果集中取出一行数据：FetchResult。

取出一行数据之后，在这一行数据中，取每个字段的值：GetColumn。（由于本人的业务需要，目前仅提供支持7种数据类型：int，unsigned int，long long，unsigned long long，float，字符串，Blob）。

每一行数据都处理完之后，释放结果集：FreeResult。（如果不释放，在下次执行查询之前，会强制释放，对象析构时，会强制释放）。

QueryOperatorSelect.h

#ifndef __QueryOperatorSelect_H__#define	__QueryOperatorSelect_H__struct st_MySQL;typedef struct st_mysql MYSQL;struct st_mysql_res;typedef struct st_mysql_res MYSQL_RES;typedef char** MYSQL_ROW;namespace common{	namespace db{		class QueryOperatorSelect		{		public:			QueryOperatorSelect();			~QueryOperatorSelect();			void Release();			// 执行sql			bool DoOperator(MYSQL *connect, const char *sql);			// 获取一条结果			bool FetchResult();						// 获取一条结果一列的值			bool GetColumn(int& value, unsigned int index);			bool GetColumn(unsigned int& value, unsigned int index);			bool GetColumn(long long& value, unsigned int index);			bool GetColumn(unsigned long long& value, unsigned int index);			bool GetColumn(float& value, unsigned int index);			bool GetColumn(void* value, unsigned int index);			// 释放结果			bool FreeResult();		PRivate:			MYSQL_RES *m_Data;				// 结果集数据			unsigned int m_FieldCount;		// 结果集列数			MYSQL_ROW m_Columns;			// 数据每一列的值			unsigned long *m_ColumnLens;	// 数据每一列的长度		};	}}#endifQueryOperatorSelect.cpp
#include "QueryOperatorSelect.h"#ifdef WIN32#include <winsock2.h>#endif#include <stdio.h>#include <mysql.h>#include <string.h>#include <stdarg.h>#include "DBOperator.h"namespace common{	namespace db{		QueryOperatorSelect::QueryOperatorSelect()		{			m_Data = NULL;			m_FieldCount = 0;			m_Columns = NULL;			m_ColumnLens = NULL;		}		QueryOperatorSelect::~QueryOperatorSelect()		{			Release();		}		void QueryOperatorSelect::Release()		{			if (NULL != m_Data)			{				DBOperator::FreeResult(m_Data);				m_Data = NULL;			}			if (NULL != m_Columns)			{				m_Columns = NULL;			}		}		bool QueryOperatorSelect::DoOperator(MYSQL *connect, const char *sql)		{			if (NULL != connect && NULL != sql)			{				if (NULL != m_Data)				{					DBOperator::FreeResult(m_Data);					m_Data = NULL;				}				if (DBOperator::ExecQuery(connect, sql))				{					m_Data = DBOperator::SelectResult(connect);					if (NULL != m_Data)					{						m_FieldCount = DBOperator::GetResultFields(m_Data);						return true;					}					else					{						m_FieldCount = 0;						return false;					}				}				else				{					return false;				}			}			else			{				return false;			}		}		bool QueryOperatorSelect::FetchResult()		{			if (NULL != m_Data)			{				m_Columns = DBOperator::GetNextResult(m_Data);				m_ColumnLens = DBOperator::GetResultLens(m_Data);				if (NULL != m_Columns && NULL != m_ColumnLens)				{					return true;				}				else				{					DBOperator::FreeResult(m_Data);					m_Data = NULL;					m_ColumnLens = NULL;					return false;				}			}			else			{				return false;			}		}		bool QueryOperatorSelect::GetColumn(int& value, unsigned int index)		{			if (NULL != m_Columns && index < m_FieldCount)			{				sscanf(m_Columns[index], "%d", &value);				return true;			}			else			{				return false;			}		}		bool QueryOperatorSelect::GetColumn(unsigned int& value, unsigned int index)		{			if (NULL != m_Columns && index < m_FieldCount)			{				sscanf(m_Columns[index], "%u", &value);				return true;			}			else			{				return false;			}		}		bool QueryOperatorSelect::GetColumn(long long& value, unsigned int index)		{			if (NULL != m_Columns && index < m_FieldCount)			{				sscanf(m_Columns[index], "%lld", &value);				return true;			}			else			{				return false;			}		}		bool QueryOperatorSelect::GetColumn(unsigned long long& value, unsigned int index)		{			if (NULL != m_Columns && index < m_FieldCount)			{				sscanf(m_Columns[index], "%llu", &value);				return true;			}			else			{				return false;			}		}		bool QueryOperatorSelect::GetColumn(float& value, unsigned int index)		{			if (NULL != m_Columns && index < m_FieldCount)			{				sscanf(m_Columns[index], "%f", &value);				return true;			}			else			{				return false;			}		}		bool QueryOperatorSelect::GetColumn(void* value, unsigned int index)		{			if (NULL != m_Columns && NULL != m_ColumnLens && index < m_FieldCount)			{				memcpy(value, m_Columns[index], m_ColumnLens[index]);				return true;			}			else			{				return false;			}		}		bool QueryOperatorSelect::FreeResult()		{			if (NULL != m_Data)			{				DBOperator::FreeResult(m_Data);				m_Data = NULL;				return true;			}			else			{				return false;			}		}	}}