C/C++18_mysql.h，_mysql.cpp

Posted 2022-01-10 码农编程录

文章目录

• 1._mysql.h
• 2._mysql.cpp

---

1._mysql.h

#ifndef __MYSQL_H
#define __MYSQL_H

// C/C++库常用头文件
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

/* mysql头文件 */
#include <mysql.h>

// mysql登录环境
struct LOGINENV

  char ip[32];
  char user[32];     // 数据库的用户名
  char pass[32];     // 数据库的密码
  char dbname[51];  
  int  port;
;

// mysql执行的结果
struct CDA_DEF

  int      rc;             // 执行结果
  unsigned long rpc;       // 执行SQL语句后，影响记录的行数
  char     message[2048];  // 执行SQL语句如果失败，存放错误信息
;

/* 数据库连接池类 */
class connection

public:
  MYSQL     *m_conn;

  // 连接状态，0-未连接，1-已连接
  int m_state;

  // 服务器环境句柄
  LOGINENV m_env;

  // 自动提交标志，0-关闭自动提交；1-开启自动提交
  int m_autocommitopt; 

  // 数据库种类，固定取值为mysql
  char m_dbtype[21];

  connection();

 ~connection();

  // 连接数据库，
  // connstr的格式为：ip,username,password,dbname,port
  // autocommitopt：0-关闭自动提交，1-启用自动提交
  int connecttodb(char *connstr,char *charset,unsigned int autocommitopt=0);

  // 从connstr中解析ip,username,password,dbname,port
  void setdbopt(char *connstr);

  // 断开与数据库的连接
  int  disconnect();

  // 设置字符集，要与数据库的一致，否则中文会出现乱码
  void character(char *charset);

  // 提交事务
  int  commit(); 

  // 回滚事务
  int  rollback();

  // 获取错误信息
  void err_report();

  // 用于存放connection操作数据库的错误或最后一次执行SQL语句的结果
  CDA_DEF m_cda;
;

// 定义SQL语句中，输入和输出字段个数的最大值，256是很大的了，可以根据实际情况调整
#define MAXPARAMS  256

/* SQL语言数据操作类 */
class sqlstatement

public:
  // 与数据库连接池的状态，0-未绑定，1-已绑定
  int m_state;

  // 语句句柄
  MYSQL_STMT *m_handle;
  
  // 输入参数
  MYSQL_BIND params_in[MAXPARAMS];
  // 输出参数
  MYSQL_BIND params_out[MAXPARAMS];

  connection *m_conn;

  // SQL语句
  char m_sql[10240];

  // 执行结果
  CDA_DEF m_cda;

  int m_sqltype;  // 待执行的SQL语句的类型，0-查询语句；1-非查询语句

  // 自动提交标志，0-关闭自动提交；1-开启自动提交
  int m_autocommitopt; 

  sqlstatement();
  sqlstatement(connection *conn);

  void initial();

 ~sqlstatement();

  // 设定数据库连接池
  int  connect(connection *conn); 

  // 断开与数据库连接池的连接
  int  disconnect();

  // 分析SQL语句,支持存储过程,采用立刻分析的方式,即时返回分析结果
  int  prepare(const char *fmt,...);

  // 绑定输入变量的地址
  int  bindin(unsigned int position,int    *value);
  int  bindin(unsigned int position,long   *value);
  int  bindin(unsigned int position,unsigned int  *value);
  int  bindin(unsigned int position,unsigned long *value);
  int  bindin(unsigned int position,float *value);
  int  bindin(unsigned int position,double *value);
  int  bindin(unsigned int position,char   *value,unsigned int len);

  // 绑定输出变量的地址
  int  bindout(unsigned int position,int    *value);
  int  bindout(unsigned int position,long   *value);
  int  bindout(unsigned int position,unsigned int  *value);
  int  bindout(unsigned int position,unsigned long *value);
  int  bindout(unsigned int position,float *value);
  int  bindout(unsigned int position,double *value);
  int  bindout(unsigned int position,char   *value,unsigned int len);

  // 执行SQL语句
  int  execute();

  // 如果SQL语句不需要输入和输出变量，可以直接执行。
  int  execute(const char *fmt,...);

  // 取下一条记录,只有当SQL语句是查询语句时才有意义 
  int  next();

  // 错误报告
  void err_report();
;
#endif

2._mysql.cpp

#include "_mysql.h"
connection::connection()
 
  m_conn = NULL;

  m_state = 0; 

  memset(&m_env,0,sizeof(LOGINENV));

  memset(&m_cda,0,sizeof(m_cda));

  m_cda.rc=-1;
  strncpy(m_cda.message,"database not open.",128);

  // 数据库种类
  memset(m_dbtype,0,sizeof(m_dbtype));
  strcpy(m_dbtype,"mysql");


connection::~connection()

  disconnect();


// 从connstr中解析username,password,tnsname
// "120.77.115.3","szidc","SZmb1601","lxqx",3306
void connection::setdbopt(char *connstr)

  memset(&m_env,0,sizeof(LOGINENV));

  char *bpos,*epos;

  bpos=epos=0;

  // ip
  bpos=connstr;
  epos=strstr(bpos,",");
  if (epos > 0) 
  
    strncpy(m_env.ip,bpos,epos-bpos); 
  else return;

  // user
  bpos=epos+1;
  epos=0;
  epos=strstr(bpos,",");
  if (epos > 0) 
  
    strncpy(m_env.user,bpos,epos-bpos); 
  else return;

  // pass
  bpos=epos+1;
  epos=0;
  epos=strstr(bpos,",");
  if (epos > 0) 
  
    strncpy(m_env.pass,bpos,epos-bpos); 
  else return;

  // dbname
  bpos=epos+1;
  epos=0;
  epos=strstr(bpos,",");
  if (epos > 0) 
  
    strncpy(m_env.dbname,bpos,epos-bpos); 
  else return;

  // port
  m_env.port=atoi(epos+1);


int connection::connecttodb(char *connstr,char *charset,unsigned int autocommitopt)

  // 如果已连接上数据库，就不再连接
  // 所以，如果想重连数据库，必须显示的调用disconnect()方法后才能重连
  if (m_state == 1) return 0;

  // 从connstr中解析username,password,tnsname
  setdbopt(connstr);

  memset(&m_cda,0,sizeof(m_cda));

  if ( (m_conn = mysql_init(NULL)) == NULL )
  
    m_cda.rc=-1; strncpy(m_cda.message,"initialize mysql failed.\\n",128); return -1;
  

  if ( mysql_real_connect(m_conn,m_env.ip,m_env.user,m_env.pass,m_env.dbname,m_env.port, NULL, 0 ) == NULL )
  
    m_cda.rc=mysql_errno(m_conn); strncpy(m_cda.message,mysql_error(m_conn),2000); mysql_close(m_conn); m_conn=NULL;  return -1;
  

  // 设置事务模式，0-关闭自动提交，1-开启自动提交
  m_autocommitopt=autocommitopt;

  if ( mysql_autocommit(m_conn, m_autocommitopt ) != 0 )
  
    m_cda.rc=mysql_errno(m_conn); strncpy(m_cda.message,mysql_error(m_conn),2000); mysql_close(m_conn); m_conn=NULL;  return -1;
  

  // 设置字符集
  character(charset);

  m_state = 1;

  return 0;


// 设置字符集，要与数据库的一致，否则中文会出现乱码
void connection::character(char *charset)

  mysql_set_character_set(m_conn,charset);

  return;


int connection::disconnect()

  memset(&m_cda,0,sizeof(m_cda));

  if (m_state == 0) 
   
    m_cda.rc=-1; strncpy(m_cda.message,"database not open.",128); return -1;
  

  rollback();

  mysql_close(m_conn); 

  m_conn=NULL;

  m_state = 0;    

  return 0;


int connection::rollback()
 
  memset(&m_cda,0,sizeof(m_cda));

  if (m_state == 0) 
   
    m_cda.rc=-1; strncpy(m_cda.message,"database not open.",128); return -1;
  

  if ( mysql_rollback(m_conn ) != 0 )
  
    m_cda.rc=mysql_errno(m_conn); strncpy(m_cda.message,mysql_error(m_conn),2000); mysql_close(m_conn); m_conn=NULL;  return -1;
  

  return 0;    


int connection::commit()
 
  memset(&m_cda,0,sizeof(m_cda));

  if (m_state == 0) 
   
    m_cda.rc=-1; strncpy(m_cda.message,"database not open.",128); return -1;
  

  if ( mysql_commit(m_conn ) != 0 )
  
    m_cda.rc=mysql_errno(m_conn); strncpy(m_cda.message,mysql_error(m_conn),2000); mysql_close(m_conn); m_conn=NULL;  return -1;
  

  return 0;


void connection::err_report()

  if (m_state == 0) 
   
    m_cda.rc=-1; strncpy(m_cda.message,"database not open.",128); return;
  

  memset(&m_cda,0,sizeof(m_cda));

  m_cda.rc=-1;
  strncpy(m_cda.message,"call err_report failed.",128);

  m_cda.rc=mysql_errno(m_conn);

  strncpy(m_cda.message,mysql_error(m_conn),1024);

  return;


sqlstatement::sqlstatement()

  initial();


void sqlstatement::initial()

  m_state=0;

  m_handle=NULL;

  memset(&m_cda,0,sizeof(m_cda));

  memset(m_sql,0,sizeof(m_sql));

  m_cda.rc=-1;
  strncpy(m_cda.message,"sqlstatement not connect to connection.\\n",128);


sqlstatement::sqlstatement(connection *conn)

  initial();

  connect(conn);


sqlstatement::~sqlstatement()

  disconnect();


int sqlstatement::connect(connection *conn)

  // 注意，一个sqlstatement在程序中只能连一个connection，不允许连多个connection
  // 所以，只要这个光标已打开，就不允许再次打开，直接返回成功
  if ( m_state == 1 ) return 0;
  
  memset(&m_cda,0,sizeof(m_cda));

  m_conn=conn;

  // 如果数据库连接类的指针为空，直接返回失败
  if (m_conn == 0)
  
    m_cda.rc=-1; strncpy(m_cda.message,"database not open.\\n",128); return -1;
  
  
  // 如果数据库没有连接好，直接返回失败
  if (m_conn->m_state == 0)
  
    m_cda.rc=-1; strncpy(m_cda.message,"database not open.\\n",128); return -1;
  

  if ( (m_handle=mysql_stmt_init(m_conn->m_conn)) == NULL)
  
    err_report(); return m_cda.rc;
  

  m_state = 1;  // 光标成功打开

  m_autocommitopt=m_conn->m_autocommitopt;

  return 0;


int sqlstatement::disconnect()

  if (m_state == 0) return 0;

  memset(&m_cda,0,sizeof(m_cda));

  mysql_stmt_close(m_handle);

  m_state=0;

  m_handle=NULL;

  memset(&m_cda,0,sizeof(m_cda));

  memset(m_sql,0,sizeof(m_sql));

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