<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >mysqli_change_user</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="MySQLi 扩展库" HREF="ref.mysqli.html"><LINK REL="PREVIOUS" TITLE="mysqli_bind_result" HREF="function.mysqli-bind-result.html"><LINK REL="NEXT" TITLE="mysqli_character_set_name" HREF="function.mysqli-character-set-name.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.mysqli-bind-result.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.mysqli-character-set-name.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.mysqli-change-user" ></A >mysqli_change_user</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN137562" ></A ><P > (PHP 5)</P >mysqli_change_user<P > (no version information, might be only in CVS)</P >mysqli->change_user() -- Changes the user of the specified database connection</DIV ><DIV CLASS="refsect1" ><A NAME="AEN137566" ></A ><H2 >说明</H2 ><P >Procedural style:</P >bool <B CLASS="methodname" >mysqli_change_user</B > ( mysqli link, string user, string password, string database )<BR ></BR ><P >Object oriented style (method):</P >class <B CLASS="classname" >mysqli</B > { <BR ></BR >bool <B CLASS="methodname" >change_user</B > ( string user, string password, string database )<BR ></BR >}<P > Changes the user of the specified database connection and sets the current database. </P ><P > In order to successfully change users a valid <CODE CLASS="parameter" >username</CODE > and <CODE CLASS="parameter" >password</CODE > parameters must be provided and that user must have sufficient permissions to access the desired database. If for any reason authorization fails, the current user authentication will remain. </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN137604" ></A ><H2 >参数</H2 ><P > <P ></P ><DIV CLASS="variablelist" ><DL ><DT ><CODE CLASS="parameter" > link</CODE ></DT ><DD ><P >Procedural style only: A link identifier returned by <A HREF="function.mysqli-connect.html" ><B CLASS="function" >mysqli_connect()</B ></A > or <A HREF="function.mysqli-init.html" ><B CLASS="function" >mysqli_init()</B ></A > </P ></DD ><DT ><CODE CLASS="parameter" >user</CODE ></DT ><DD ><P > The MySQL user name. </P ></DD ><DT ><CODE CLASS="parameter" >password</CODE ></DT ><DD ><P > The MySQL password. </P ></DD ><DT ><CODE CLASS="parameter" >database</CODE ></DT ><DD ><P > The database to change to. </P ><P > If desired, the <TT CLASS="constant" ><B >NULL</B ></TT > value may be passed resulting in only changing the user and not selecting a database. To select a database in this case use the <A HREF="function.mysqli-select-db.html" ><B CLASS="function" >mysqli_select_db()</B ></A > function. </P ></DD ></DL ></DIV > </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN137633" ></A ><H2 >返回值</H2 ><P > 如果成功则返回 <TT CLASS="constant" ><B >TRUE</B ></TT >,失败则返回 <TT CLASS="constant" ><B >FALSE</B ></TT >。 </P ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN137638" ></A ><H2 >注释</H2 ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >注意: </B > Using this command will always cause the current database connection to behave as if was a completely new database connection, regardless of if the operation was completed successfully. This reset includes performing a rollback on any active transactions, closing all temporary tables, and unlocking all locked tables. </P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN137642" ></A ><H2 >范例</H2 ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN137644" ></A ><P ><B >例 1. Object oriented style</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /><br /></font><font color="#FF8000">/* connect database test */<br /></font><font color="#0000BB">$mysqli </font><font color="#007700">= new </font><font color="#0000BB">mysqli</font><font color="#007700">(</font><font color="#DD0000">"localhost"</font><font color="#007700">, </font><font color="#DD0000">"my_user"</font><font color="#007700">, </font><font color="#DD0000">"my_password"</font><font color="#007700">, </font><font color="#DD0000">"test"</font><font color="#007700">);<br /><br /></font><font color="#FF8000">/* check connection */<br /></font><font color="#007700">if (</font><font color="#0000BB">mysqli_connect_errno</font><font color="#007700">()) {<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Connect failed: %s\n"</font><font color="#007700">, </font><font color="#0000BB">mysqli_connect_error</font><font color="#007700">());<br /> exit();<br />}<br /><br /></font><font color="#FF8000">/* Set Variable a */<br /></font><font color="#0000BB">$mysqli</font><font color="#007700">-></font><font color="#0000BB">query</font><font color="#007700">(</font><font color="#DD0000">"SET @a:=1"</font><font color="#007700">);<br /><br /></font><font color="#FF8000">/* reset all and select a new database */<br /></font><font color="#0000BB">$mysqli</font><font color="#007700">-></font><font color="#0000BB">change_user</font><font color="#007700">(</font><font color="#DD0000">"my_user"</font><font color="#007700">, </font><font color="#DD0000">"my_password"</font><font color="#007700">, </font><font color="#DD0000">"world"</font><font color="#007700">);<br /><br />if (</font><font color="#0000BB">$result </font><font color="#007700">= </font><font color="#0000BB">$mysqli</font><font color="#007700">-></font><font color="#0000BB">query</font><font color="#007700">(</font><font color="#DD0000">"SELECT DATABASE()"</font><font color="#007700">)) {<br /> </font><font color="#0000BB">$row </font><font color="#007700">= </font><font color="#0000BB">$result</font><font color="#007700">-></font><font color="#0000BB">fetch_row</font><font color="#007700">();<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Default database: %s\n"</font><font color="#007700">, </font><font color="#0000BB">$row</font><font color="#007700">[</font><font color="#0000BB">0</font><font color="#007700">]);<br /> </font><font color="#0000BB">$result</font><font color="#007700">-></font><font color="#0000BB">close</font><font color="#007700">();<br />}<br /><br />if (</font><font color="#0000BB">$result </font><font color="#007700">= </font><font color="#0000BB">$mysqli</font><font color="#007700">-></font><font color="#0000BB">query</font><font color="#007700">(</font><font color="#DD0000">"SELECT @a"</font><font color="#007700">)) {<br /> </font><font color="#0000BB">$row </font><font color="#007700">= </font><font color="#0000BB">$result</font><font color="#007700">-></font><font color="#0000BB">fetch_row</font><font color="#007700">();<br /> if (</font><font color="#0000BB">$row</font><font color="#007700">[</font><font color="#0000BB">0</font><font color="#007700">] === </font><font color="#0000BB">NULL</font><font color="#007700">) {<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Value of variable a is NULL\n"</font><font color="#007700">);<br /> }<br /> </font><font color="#0000BB">$result</font><font color="#007700">-></font><font color="#0000BB">close</font><font color="#007700">();<br />}<br /><br /></font><font color="#FF8000">/* close connection */<br /></font><font color="#0000BB">$mysqli</font><font color="#007700">-></font><font color="#0000BB">close</font><font color="#007700">();<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN137647" ></A ><P ><B >例 2. Procedural style</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /></font><font color="#FF8000">/* connect database test */<br /></font><font color="#0000BB">$link </font><font color="#007700">= </font><font color="#0000BB">mysqli_connect</font><font color="#007700">(</font><font color="#DD0000">"localhost"</font><font color="#007700">, </font><font color="#DD0000">"my_user"</font><font color="#007700">, </font><font color="#DD0000">"my_password"</font><font color="#007700">, </font><font color="#DD0000">"test"</font><font color="#007700">);<br /><br /></font><font color="#FF8000">/* check connection */<br /></font><font color="#007700">if (!</font><font color="#0000BB">$link</font><font color="#007700">) {<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Connect failed: %s\n"</font><font color="#007700">, </font><font color="#0000BB">mysqli_connect_error</font><font color="#007700">());<br /> exit();<br />}<br /><br /></font><font color="#FF8000">/* Set Variable a */<br /></font><font color="#0000BB">mysqli_query</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">, </font><font color="#DD0000">"SET @a:=1"</font><font color="#007700">);<br /><br /></font><font color="#FF8000">/* reset all and select a new database */<br /></font><font color="#0000BB">mysqli_change_user</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">, </font><font color="#DD0000">"my_user"</font><font color="#007700">, </font><font color="#DD0000">"my_password"</font><font color="#007700">, </font><font color="#DD0000">"world"</font><font color="#007700">);<br /><br />if (</font><font color="#0000BB">$result </font><font color="#007700">= </font><font color="#0000BB">mysqli_query</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">, </font><font color="#DD0000">"SELECT DATABASE()"</font><font color="#007700">)) {<br /> </font><font color="#0000BB">$row </font><font color="#007700">= </font><font color="#0000BB">mysqli_fetch_row</font><font color="#007700">(</font><font color="#0000BB">$result</font><font color="#007700">);<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Default database: %s\n"</font><font color="#007700">, </font><font color="#0000BB">$row</font><font color="#007700">[</font><font color="#0000BB">0</font><font color="#007700">]);<br /> </font><font color="#0000BB">mysqli_free_result</font><font color="#007700">(</font><font color="#0000BB">$result</font><font color="#007700">);<br />}<br /><br />if (</font><font color="#0000BB">$result </font><font color="#007700">= </font><font color="#0000BB">mysqli_query</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">, </font><font color="#DD0000">"SELECT @a"</font><font color="#007700">)) {<br /> </font><font color="#0000BB">$row </font><font color="#007700">= </font><font color="#0000BB">mysqli_fetch_row</font><font color="#007700">(</font><font color="#0000BB">$result</font><font color="#007700">);<br /> if (</font><font color="#0000BB">$row</font><font color="#007700">[</font><font color="#0000BB">0</font><font color="#007700">] === </font><font color="#0000BB">NULL</font><font color="#007700">) {<br /> </font><font color="#0000BB">printf</font><font color="#007700">(</font><font color="#DD0000">"Value of variable a is NULL\n"</font><font color="#007700">);<br /> }<br /> </font><font color="#0000BB">mysqli_free_result</font><font color="#007700">(</font><font color="#0000BB">$result</font><font color="#007700">);<br />}<br /><br /></font><font color="#FF8000">/* close connection */<br /></font><font color="#0000BB">mysqli_close</font><font color="#007700">(</font><font color="#0000BB">$link</font><font color="#007700">);<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE ><P >上例将输出:</P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="screen" >Default database: world Value of variable a is NULL</PRE ></TD ></TR ></TABLE ></DIV ><DIV CLASS="refsect1" ><A NAME="AEN137652" ></A ><H2 >参见</H2 ><P > <P ></P ><TABLE BORDER="0" ><TBODY ><TR ><TD ><A HREF="function.mysqli-connect.html" ><B CLASS="function" >mysqli_connect()</B ></A ></TD ></TR ><TR ><TD ><A HREF="function.mysqli-select-db.html" ><B CLASS="function" >mysqli_select_db()</B ></A ></TD ></TR ></TBODY ></TABLE ><P ></P > </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.mysqli-bind-result.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.mysqli-character-set-name.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >mysqli_bind_result</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.mysqli.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >mysqli_character_set_name</TD ></TR ></TABLE ></DIV ></BODY ></HTML >