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195 lines
20 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>设置预提取行数</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.oci-set-prefetch" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">oci_set_prefetch</h1>
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<p class="verinfo">(PHP 5, PHP 7, PECL OCI8 >= 1.1.0)</p><p class="refpurpose"><span class="refname">oci_set_prefetch</span> — <span class="dc-title">设置预提取行数</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.oci-set-prefetch-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>oci_set_prefetch</strong></span>
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( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$statement</code></span>
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[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$rows</code></span>
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] ) : <span class="type">bool</span></div>
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<p class="para rdfs-comment">
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在成功调用 <span class="function"><a href="oci_execute.html" class="function">oci_execute()</a></span>
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之后设定预提取的行数。<code class="parameter">rows</code> 的默认值为 1。
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</p>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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在 PHP 5.0.0 之前的版本必须使用 <span class="function"><a href="ocisetprefetch.html" class="function">ocisetprefetch()</a></span>
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替代本函数。该函数名仍然可用，为向下兼容作为
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<span class="function"><strong>oci_set_prefetch()</strong></span> 的别名。不过其已被废弃，不推荐使用。
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</p>
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</p></blockquote>
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<p class="para">
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成功时返回 <strong><code>TRUE</code></strong>， 或者在失败时返回 <strong><code>FALSE</code></strong>。
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</p>
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<p class="simpara">
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参见 <a href="oci8.configuration.html#ini.oci8.default-prefetch" class="link">oci8_.default_prefetch</a>
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INI 选项。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.oci-set-prefetch-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">statement</code></dt>
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<dd>
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<p class="para">有效的 OCI8 报表标识符
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由 <span class="function"><a href="oci_parse.html" class="function">oci_parse()</a></span> 创建，被 <span class="function"><a href="oci_execute.html" class="function">oci_execute()</a></span>
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或 <em>REF CURSOR</em> statement 标识执行。</p>
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</dd>
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<dt>
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<code class="parameter">rows</code></dt>
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<dd>
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<p class="para">
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The number of rows to be prefetched, >= 0
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.oci-set-prefetch-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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成功时返回 <strong><code>TRUE</code></strong>， 或者在失败时返回 <strong><code>FALSE</code></strong>。
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</p>
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</div>
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<div class="refsect1 changelog" id="refsect1-function.oci-set-prefetch-changelog">
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<h3 class="title">更新日志</h3>
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<p class="para">
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<table class="doctable informaltable">
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<thead>
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<tr>
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<th>版本</th>
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<th>说明</th>
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</tr>
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</thead>
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<tbody class="tbody">
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<tr>
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<td>PHP 5.3.2 (PECL OCI8 1.4)</td>
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<td>
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Before this release, <code class="parameter">rows</code> must be >= 1.
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</td>
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</tr>
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<tr>
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<td>PHP 5.3 (PECL OCI8 1.3.4)</td>
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<td>
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Before this release, prefetching was limited to the lesser
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of <code class="parameter">rows</code> rows and 1024
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* <code class="parameter">rows</code> bytes. The byte size
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restriction has now been removed.
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</td>
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</tr>
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</tbody>
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</table>
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.oci-set-prefetch-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-2461">
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<p><strong>Example #1 Changing the default prefetch value for a query</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /><br />$conn </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'hr'</span><span style="color: #007700">, </span><span style="color: #DD0000">'welcome'</span><span style="color: #007700">, </span><span style="color: #DD0000">'localhost/XE'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$stid </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_parse</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">'SELECT * FROM myverybigtable'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_set_prefetch</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">, </span><span style="color: #0000BB">300</span><span style="color: #007700">); </span><span style="color: #FF8000">// Set before calling oci_execute()<br /></span><span style="color: #0000BB">oci_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">"<table border='1'>\n"</span><span style="color: #007700">;<br />while (</span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_fetch_array</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">, </span><span style="color: #0000BB">OCI_ASSOC</span><span style="color: #007700">+</span><span style="color: #0000BB">OCI_RETURN_NULLS</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"<tr>\n"</span><span style="color: #007700">;<br /> foreach (</span><span style="color: #0000BB">$row </span><span style="color: #007700">as </span><span style="color: #0000BB">$item</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">" <td>"</span><span style="color: #007700">.(</span><span style="color: #0000BB">$item </span><span style="color: #007700">!== </span><span style="color: #0000BB">null </span><span style="color: #007700">? </span><span style="color: #0000BB">htmlentities</span><span style="color: #007700">(</span><span style="color: #0000BB">$item</span><span style="color: #007700">, </span><span style="color: #0000BB">ENT_QUOTES</span><span style="color: #007700">) : </span><span style="color: #DD0000">"&nbsp;"</span><span style="color: #007700">).</span><span style="color: #DD0000">"</td>\n"</span><span style="color: #007700">;<br /> }<br /> echo </span><span style="color: #DD0000">"</tr>\n"</span><span style="color: #007700">;<br />}<br />echo </span><span style="color: #DD0000">"</table>\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">oci_free_statement</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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<p class="para">
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<div class="example" id="example-2462">
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<p><strong>Example #2 Changing the default prefetch for a REF CURSOR fetch</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/*<br /> Create the PL/SQL stored procedure as:<br /><br /> CREATE OR REPLACE PROCEDURE myproc(p1 OUT SYS_REFCURSOR) AS<br /> BEGIN<br /> OPEN p1 FOR SELECT * FROM all_objects WHERE ROWNUM < 5000;<br /> END;<br />*/<br /><br /></span><span style="color: #0000BB">$conn </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'hr'</span><span style="color: #007700">, </span><span style="color: #DD0000">'welcome'</span><span style="color: #007700">, </span><span style="color: #DD0000">'localhost/XE'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$stid </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_parse</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">'BEGIN myproc(:rc); END;'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$refcur </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_new_cursor</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_bind_by_name</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">, </span><span style="color: #DD0000">':rc'</span><span style="color: #007700">, </span><span style="color: #0000BB">$refcur</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">OCI_B_CURSOR</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Change the prefetch before executing the cursor.<br />// REF CURSOR prefetching works when PHP is linked with Oracle 11gR2 Client libraries<br /></span><span style="color: #0000BB">oci_set_prefetch</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">, </span><span style="color: #0000BB">200</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">"<table border='1'>\n"</span><span style="color: #007700">;<br />while (</span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_fetch_array</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">, </span><span style="color: #0000BB">OCI_ASSOC</span><span style="color: #007700">+</span><span style="color: #0000BB">OCI_RETURN_NULLS</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">"<tr>\n"</span><span style="color: #007700">;<br /> foreach (</span><span style="color: #0000BB">$row </span><span style="color: #007700">as </span><span style="color: #0000BB">$item</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">" <td>"</span><span style="color: #007700">.(</span><span style="color: #0000BB">$item </span><span style="color: #007700">!== </span><span style="color: #0000BB">null </span><span style="color: #007700">? </span><span style="color: #0000BB">htmlentities</span><span style="color: #007700">(</span><span style="color: #0000BB">$item</span><span style="color: #007700">, </span><span style="color: #0000BB">ENT_QUOTES</span><span style="color: #007700">) : </span><span style="color: #DD0000">"&nbsp;"</span><span style="color: #007700">).</span><span style="color: #DD0000">"</td>\n"</span><span style="color: #007700">;<br /> }<br /> echo </span><span style="color: #DD0000">"</tr>\n"</span><span style="color: #007700">;<br />}<br />echo </span><span style="color: #DD0000">"</table>\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">oci_free_statement</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_free_statement</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_close</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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<p class="para">
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If PHP OCI8 fetches from a REF CURSOR and then passes the REF
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CURSOR back to a second PL/SQL procedure for further processing,
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then set the REF CURSOR prefetch count to <strong><code>0</code></strong> to
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avoid rows being "lost" from the result set. The prefetch value is
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the number of extra rows fetched in each OCI8 internal request to
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the database, so setting it to <strong><code>0</code></strong> means only
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fetch one row at a time.
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<div class="example" id="example-2463">
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<p><strong>Example #3 Setting the prefetch value when passing a REF CURSOR back to Oracle</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<span style="color: #0000BB"><?php<br /><br />$conn </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'hr'</span><span style="color: #007700">, </span><span style="color: #DD0000">'welcome'</span><span style="color: #007700">, </span><span style="color: #DD0000">'localhost/orcl'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// get the REF CURSOR<br /></span><span style="color: #0000BB">$stid </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_parse</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">'BEGIN myproc(:rc_out); END;'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$refcur </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_new_cursor</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_bind_by_name</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">, </span><span style="color: #DD0000">':rc_out'</span><span style="color: #007700">, </span><span style="color: #0000BB">$refcur</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">OCI_B_CURSOR</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Display two rows, but don't prefetch any extra rows otherwise<br />// those extra rows would not be passed back to myproc_use_rc().<br />// A prefetch value of 0 is allowed in PHP 5.3.2 and PECL OCI8 1.4<br /></span><span style="color: #0000BB">oci_set_prefetch</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_fetch_array</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$row</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$row </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_fetch_array</span><span style="color: #007700">(</span><span style="color: #0000BB">$refcur</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$row</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// pass the REF CURSOR to myproc_use_rc() to do more data processing<br />// with the result set<br /></span><span style="color: #0000BB">$stid </span><span style="color: #007700">= </span><span style="color: #0000BB">oci_parse</span><span style="color: #007700">(</span><span style="color: #0000BB">$conn</span><span style="color: #007700">, </span><span style="color: #DD0000">'begin myproc_use_rc(:rc_in); end;'</span><span style="color: #007700">); <br /></span><span style="color: #0000BB">oci_bind_by_name</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">, </span><span style="color: #DD0000">':rc_in'</span><span style="color: #007700">, </span><span style="color: #0000BB">$refcur</span><span style="color: #007700">, -</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">OCI_B_CURSOR</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">oci_execute</span><span style="color: #007700">(</span><span style="color: #0000BB">$stid</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
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</span>
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 notes" id="refsect1-function.oci-set-prefetch-notes">
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<h3 class="title">注释</h3>
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<blockquote class="note"><p><strong class="note">Note</strong>:
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<p class="para">
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In PHP versions before 5.0.0 use <span class="function"><a href="ocisetprefetch.html" class="function">ocisetprefetch()</a></span> instead. 在当前版本中，旧的函数名还可以被使用，但已经被废弃并不建议使用。
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</p>
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</p></blockquote>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.oci-set-prefetch-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member">
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<a href="oci8.configuration.html#ini.oci8.default-prefetch" class="link">oci8.default_prefetch</a>
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ini option
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</li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |