SQLite3的绑定函数族使用与其注意事项详解

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 work
PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE work (baodanhao text unique primary key , chudanriqi text,qudao text,lianxiren text,xiaoshou text,beibaorenxingming text,chufar
iqi text,baoxianpinpai text,baoxianjihua text,baoxianjine real,yongjinbilv real,jingbaofei real,huankuanfangshi text,haikuanjine real,huanku
anriqi text,shifouquane text,lirunbilv real,lirunjine real,huoliriqi text,fapiaojisong text,shifubaoxiangongsi text,beizhu text);

总结

以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作能带来一定的帮助,如果有疑问大家可以留言交流,谢谢大家对软件开发网的支持。

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