PHP数据库连接的方法是什么

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　　4.1 连接

if ($conn=Ora_Logon("user@TNSNAME","password"))

{

echo "SUCCESS ! Connected to database ";

}

else

{

echo "Failed :-( Could not connect to database ";

}

Ora_Logoff($conn);

phpinfo();

?>

以上代码使用TNSNAME(在你的文件中指明)定义的`Oracle数据库名称、用户名称和密码连接数据库。在成功连接的基础上，ora_logon函数返回一个非零的连接ID并储存在变量$conn中。

　　4.2 查询

假设与数据库已经连接就绪，下面我们就来实际的应用对数据库的查询。下面的代码演示了一个连接并查询的典型例子：

以下是引用片段：

/*

* 连接数据库并执行查询

*/

function printoraerr($in_cur)

{

// 检查Oracle是否出错

// 如果存在错误则显示

// 当指针被激活时每次请求Oracle后调用该函数

if(ora_errorcode($in_cur))

echo "Oracle code - "_error($in_cur)." ";

return;

}

/** 主程序 */

if (!($conn=ora_logon("user@TNSNAME","password")))

{

echo "Connection to database failed ";

exit;

}

echo "Connected as connection - $conn

";

echo "Opening cursor ...

";

$cursor=ora_open($conn); printoraerr($cursor);

echo "Opened cursor - $cursor

";

$qry="select user,sysdate from dual";

echo "Parsing the query $qry ...

";

ora_parse($cursor,$qry,0); printoraerr($cursor);

echo "Query parsed

";

echo "Executing cursor ...

";

ora_exec($cursor); printoraerr($cursor);

echo "Executed cursor

";

echo "Fetching cursor ...

";

while(ora_fetch($cursor))

{

$user=ora_getcolumn($cursor,0); printoraerr($cursor);

$sysdate=ora_getcolumn($cursor,1); printoraerr($cursor);

echo " row = $user, $sysdate

";

}

echo "Fetched all records

";

echo "Closing cursor ...

";

ora_close($cursor);

echo "Closed cursor

";

echo "Logging off from oracle...

";

ora_logoff($conn);

echo "Logged off from oracle

";

?>

(译者注：以上代码段缺少注释，请读者参考PHP Manual的Oracle数据库函数部分)

　　4.3 显示结果

以下代码演示了怎样查询数据库并将结果输出：

以下是引用片段：

function printoraerr($in_cur, $conn)

{

// 检查Oracle是否出错

// 如果存在错误则显示

// 当指针被激活时每次请求Oracle后调用该函数

// If it encountered an error, we exit immediately

if(ora_errorcode($in_cur))

{

echo "Oracle code - "_error($in_cur)."

n";

ora_logoff($conn);

exit;

}

return;

}

function exequery($w_qry,$conn)

{

$cursor=ora_open($conn); printoraerr($cursor,$conn);

ora_parse($cursor,$w_qry,0); printoraerr($cursor,$conn);

ora_exec($cursor); printoraerr($cursor,$conn);

$numrows=0;

$w_numcols=ora_numcols($cursor);

// 显示头部

echo "

";

for ($i=0;$i<$w_numcols;$i++)

{

$align=(ora_columntype($cursor,$i)=="NUMBER")?"RIGHT":"LEFT";

echo " "_columnname($cursor,$i)." ";

}

echo "

";

while(ora_fetch($cursor))

{

echo " ";

for ($i=0;$i<$w_numcols;$i++)

{

$align=(ora_columntype($cursor,$i)=="NUMBER")?"RIGHT":"LEFT";

if(ora_columntype($cursor,$i)=="LONG")

echo " ".

ora_getcolumn($cursor,$i)."

";

else

echo " "_getcolumn($cursor,$i)." ";

printoraerr($cursor,$conn);

}