数据库MySql类库系列(四)-QueryOperatorSelect

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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sqlbool 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};}}#endif

QueryOperatorSelect.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;}}}}

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