SQLite3的绑定函数族使用与其注意事项详解
<p><span style="color: #ff0000"><strong>前言</strong></span></p><p>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。</p>
<p><strong>下面的代码，有一个问题，插入后的东西一定是：</strong></p>
<div class="jb51code">
<pre class="brush:sql;">
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);</pre>
</div>
<p><span style="color: #ff0000"><strong>看看有问题的代码：</strong></span></p>
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<pre class="brush:sql;">
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);</pre>
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<p>为什么呢？<br />
</p>
<p>因为，sqlite3_bind_text绑定的text，需要在做：<br />
</p>
<div class="jb51code">
<pre class="brush:sql;">
rc = sqlite3_step(stmt); </pre>
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<p>的时候统一提交，而上面的代码使用的临时变量，<code>rc = sqlite3_step(stmt);</code>的时候，早就不存在了。因此乱码也是正常的。</p>
<p><span style="color: #ff0000"><strong>修改如下：</strong></span></p>
<div class="jb51code">
<pre class="brush:sql;">
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;
while(count++ < ID_TOTALCOUNT)
{
DbStr.Empty();
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);
DbStr = 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.GetString(), "%lf", &tMoney);
ASSERT(rtn == 1);
rc = sqlite3_bind_double(stmt, count, tMoney);
}
else
{
rc = sqlite3_bind_text(stmt, count, DbStr.GetString(), 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);</pre>
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<p><span style="color: #ff0000"><strong>附上数据库创建的sql语法：</strong></span></p>
<div class="jb51code">
<pre class="brush:sql;">
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);</pre>
</div>
<p><span style="color: #ff0000"><strong>总结</strong></span></p>
<p>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，谢谢大家对琼殿技术社区的支持。</p>
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