SQLite3的绑定函数族使用与其注意事项详解

2020-01-31 15:11:12

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前言

本文给大家展示的代码实际上就是如何利用Sqlite3的参数化机制做数据插入，也可以update操作，就看你怎么玩了，这里只列出代码，然后说一些注意事项。

下面的代码，有一个问题，插入后的东西一定是：

INSERT INTO "work" VALUES('铪','铪铪铪铪铪',NULL,NULL,NULL,NULL,'铪铪铪铪铪',NULL,NULL,110.0,1.0,108.9,NULL,NULL,'铪铪铪铪铪',NULL,NULL,NULL,'铪铪铪铪铪',NULL,NULL,NULL);

看看有问题的代码：

sqlite3_stmt *stmt; CString sql = "insert into work values (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)"; int rc = sqlite3_prepare_v2(db, sql.GetString(), -1, &stmt, NULL); if(rc != SQLITE_OK) { MessageBox("sqlite3_prepare_v2 Failed!"); return; } count = 0; p_wnd = PrevWnd; while(count++ < ID_TOTALCOUNT) { CString DbStr;  p_wnd = CWnd::GetNextDlgTabItem(p_wnd, FALSE);  if(p_wnd == NULL) {  return; } p_wnd->GetWindowText(DbStr); do {  if(!DbStr.GetLength())  {  rc = sqlite3_bind_null(stmt, count);  break;  }  //日期相关  if( count == ID_CHUDANRIQI ||   count == ID_CHUFARIQI ||   count == ID_HUANKUANRIQI ||   count == ID_HUOLIRIQI)  {  CDateTimeCtrl *TimeCtl = (CDateTimeCtrl *)p_wnd;    CString time = DateTimeToString(*TimeCtl);  rc = sqlite3_bind_text(stmt, count, time.GetString(), time.GetLength(), SQLITE_STATIC);  break;  }  else  {  //金钱相关的处理real类型  if( count == ID_BAOXIANJINE ||    count == ID_YONGJINBILV ||    count == ID_JINGBAOFEI ||    count == ID_HUANKUANJINE ||    count == ID_LIRUNBILV ||    count == ID_LIRUNJINE)  {   double tMoney = 0.0;   int rtn = sscanf_s(DbStr.GetString(), "%lf", &tMoney);   ASSERT(rtn == 1);   rc = sqlite3_bind_double(stmt, count, tMoney);  }  else  {   char *str = (char *)DbStr.GetString();   int c = strlen(str);   int c1 = DbStr.GetLength();   rc = sqlite3_bind_text(stmt, count, DbStr.GetString(), -1/*DbStr.GetLength()*/, SQLITE_STATIC);  }  } }while(0); if(rc != SQLITE_OK) {  CString ErrStr = sqlite3_errstr(rc);  MessageBox(ErrStr);  return; } } rc = sqlite3_step(stmt);  if(rc != SQLITE_DONE) { if(rc == SQLITE_ERROR) {  CString DbErr;  DbErr.Format("Sql Insert failed, %s", sqlite3_errmsg(db));  MessageBox(DbErr); } else {  MessageBox("sqlite3_step Failed!"); }  } sqlite3_finalize(stmt);

为什么呢？

因为，sqlite3_bind_text绑定的text，需要在做：

rc = sqlite3_step(stmt);

的时候统一提交，而上面的代码使用的临时变量，rc = sqlite3_step(stmt);的时候，早就不存在了。因此乱码也是正常的。

修改如下：

sqlite3_stmt *stmt; CString sql = "insert into work values (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)"; int rc = sqlite3_prepare_v2(db, sql.GetString(), -1, &stmt, NULL); if(rc != SQLITE_OK) { MessageBox("sqlite3_prepare_v2 Failed!"); return; } count = 0; p_wnd = PrevWnd; CString DbStr[ID_TOTALCOUNT + 1]; while(count++ < ID_TOTALCOUNT) { DbStr[count].Empty();  p_wnd = CWnd::GetNextDlgTabItem(p_wnd, FALSE);  if(p_wnd == NULL) {  return; } p_wnd->GetWindowText(DbStr[count]); do {  if(!DbStr[count].GetLength())  {  rc = sqlite3_bind_null(stmt, count);  break;  }  //日期相关  if( count == ID_CHUDANRIQI ||   count == ID_CHUFARIQI ||   count == ID_HUANKUANRIQI ||   count == ID_HUOLIRIQI)  {  CDateTimeCtrl *TimeCtl = (CDateTimeCtrl *)p_wnd;    CString time = DateTimeToString(*TimeCtl);  DbStr[count] = time;  rc = sqlite3_bind_text(stmt, count, time.GetString(), time.GetLength(), SQLITE_STATIC);  }  else  {  //金钱相关的处理real类型  if( count == ID_BAOXIANJINE ||    count == ID_YONGJINBILV ||    count == ID_JINGBAOFEI ||    count == ID_HUANKUANJINE ||    count == ID_LIRUNBILV ||    count == ID_LIRUNJINE)  {   double tMoney = 0.0;   int rtn = sscanf_s(DbStr[count].GetString(), "%lf", &tMoney);   ASSERT(rtn == 1);   rc = sqlite3_bind_double(stmt, count, tMoney);  }  else  {   rc = sqlite3_bind_text(stmt, count, DbStr[count].GetString(), DbStr[count].GetLength(), SQLITE_STATIC);  }  } }while(0); if(rc != SQLITE_OK) {  CString ErrStr = sqlite3_errstr(rc);  MessageBox(ErrStr);  return; } } rc = sqlite3_step(stmt);  if(rc != SQLITE_DONE) { if(rc == SQLITE_ERROR) {  CString DbErr;  DbErr.Format("Sql Insert failed, %s", sqlite3_errmsg(db));  MessageBox(DbErr); } else {  MessageBox("sqlite3_step Failed!"); }  } sqlite3_finalize(stmt);

附上数据库创建的sql语法：

sqlite> .dump workPRAGMA foreign_keys=OFF;BEGIN TRANSACTION;CREATE TABLE work (baodanhao text unique primary key , chudanriqi text,qudao text,lianxiren text,xiaoshou text,beibaorenxingming text,chufariqi text,baoxianpinpai text,baoxianjihua text,baoxianjine real,yongjinbilv real,jingbaofei real,huankuanfangshi text,haikuanjine real,huankuanriqi text,shifouquane text,lirunbilv real,lirunjine real,huoliriqi text,fapiaojisong text,shifubaoxiangongsi text,beizhu text);

总结

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