uTools-Manuals/docs/php/pg_query_params.html
2019-04-28 19:00:34 +08:00

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<title>Submits a command to the server and waits for the result, with the ability to pass parameters separately from the SQL command text</title>
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<div id="layout-content"><div id="function.pg-query-params" class="refentry">
<div class="refnamediv">
<h1 class="refname">pg_query_params</h1>
<p class="verinfo">(PHP 5 &gt;= 5.1.0, PHP 7)</p><p class="refpurpose"><span class="refname">pg_query_params</span> &mdash; <span class="dc-title">Submits a command to the server and waits for the result, with the ability to pass parameters separately from the SQL command text</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.pg-query-params-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>pg_query_params</strong></span>
([ <span class="methodparam"><span class="type">resource</span> <code class="parameter">$connection</code></span>
], <span class="methodparam"><span class="type">string</span> <code class="parameter">$query</code></span>
, <span class="methodparam"><span class="type">array</span> <code class="parameter">$params</code></span>
) : <span class="type">resource</span></div>
<p class="para rdfs-comment">
Submits a command to the server and waits for the result, with the ability
to pass parameters separately from the SQL command text.
</p>
<p class="para">
<span class="function"><strong>pg_query_params()</strong></span> is like <span class="function"><a href="pg_query.html" class="function">pg_query()</a></span>,
but offers additional functionality: parameter
values can be specified separately from the command string proper.
<span class="function"><strong>pg_query_params()</strong></span> is supported only against PostgreSQL 7.4 or
higher connections; it will fail when using earlier versions.
</p>
<p class="para">
If parameters are used, they are referred to in the
<code class="parameter">query</code> string as $1, $2, etc. The same parameter may
appear more than once in the <code class="parameter">query</code>; the same value
will be used in that case. <code class="parameter">params</code> specifies the
actual values of the parameters. A <strong><code>NULL</code></strong> value in this array means the
corresponding parameter is SQL <em>NULL</em>.
</p>
<p class="para">
The primary advantage of <span class="function"><strong>pg_query_params()</strong></span> over <span class="function"><a href="pg_query.html" class="function">pg_query()</a></span>
is that parameter values
may be separated from the <code class="parameter">query</code> string, thus avoiding the need for tedious
and error-prone quoting and escaping. Unlike <span class="function"><a href="pg_query.html" class="function">pg_query()</a></span>,
<span class="function"><strong>pg_query_params()</strong></span> allows at
most one SQL command in the given string. (There can be semicolons in it,
but not more than one nonempty command.)
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.pg-query-params-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">connection</code></dt>
<dd>
<p class="para">
PostgreSQL database connection resource. When
<code class="parameter">connection</code> is not present, the default connection
is used. The default connection is the last connection made by
<span class="function"><a href="pg_connect.html" class="function">pg_connect()</a></span> or <span class="function"><a href="pg_pconnect.html" class="function">pg_pconnect()</a></span>.
</p>
</dd>
<dt>
<code class="parameter">query</code></dt>
<dd>
<p class="para">
The parameterized SQL statement. Must contain only a single statement.
(multiple statements separated by semi-colons are not allowed.) If any parameters
are used, they are referred to as $1, $2, etc.
</p>
<p class="para">
User-supplied values should always be passed as parameters, not
interpolated into the query string, where they form possible
<a href="security.database.sql_injection.html" class="link"> SQL injection</a>
attack vectors and introduce bugs when handling data containing quotes.
If for some reason you cannot use a parameter, ensure that interpolated
values are <a href="pg_escape_string.html" class="link">properly escaped</a>.
</p>
</dd>
<dt>
<code class="parameter">params</code></dt>
<dd>
<p class="para">
An array of parameter values to substitute for the $1, $2, etc. placeholders
in the original prepared query string. The number of elements in the array
must match the number of placeholders.
</p>
<p class="para">
Values intended for <em>bytea</em> fields are not supported as
parameters. Use <span class="function"><a href="pg_escape_bytea.html" class="function">pg_escape_bytea()</a></span> instead, or use the
large object functions.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.pg-query-params-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">
A query result resource on success 或者在失败时返回 <strong><code>FALSE</code></strong>.</p>
</div>
<div class="refsect1 examples" id="refsect1-function.pg-query-params-examples">
<h3 class="title">范例</h3>
<p class="para">
<div class="example" id="example-2512">
<p><strong>Example #1 Using <span class="function"><strong>pg_query_params()</strong></span></strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">//&nbsp;Connect&nbsp;to&nbsp;a&nbsp;database&nbsp;named&nbsp;"mary"<br /></span><span style="color: #0000BB">$dbconn&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">pg_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"dbname=mary"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Find&nbsp;all&nbsp;shops&nbsp;named&nbsp;Joe's&nbsp;Widgets.&nbsp;&nbsp;Note&nbsp;that&nbsp;it&nbsp;is&nbsp;not&nbsp;necessary&nbsp;to<br />//&nbsp;escape&nbsp;"Joe's&nbsp;Widgets"<br /></span><span style="color: #0000BB">$result&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">pg_query_params</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbconn</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'SELECT&nbsp;*&nbsp;FROM&nbsp;shops&nbsp;WHERE&nbsp;name&nbsp;=&nbsp;$1'</span><span style="color: #007700">,&nbsp;array(</span><span style="color: #DD0000">"Joe's&nbsp;Widgets"</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">//&nbsp;Compare&nbsp;against&nbsp;just&nbsp;using&nbsp;pg_query<br /></span><span style="color: #0000BB">$str&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">pg_escape_string</span><span style="color: #007700">(</span><span style="color: #DD0000">"Joe's&nbsp;Widgets"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$result&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">pg_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbconn</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"SELECT&nbsp;*&nbsp;FROM&nbsp;shops&nbsp;WHERE&nbsp;name&nbsp;=&nbsp;'</span><span style="color: #007700">{</span><span style="color: #0000BB">$str</span><span style="color: #007700">}</span><span style="color: #DD0000">'"</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.pg-query-params-seealso">
<h3 class="title">参见</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="pg_query.html" class="function" rel="rdfs-seeAlso">pg_query()</a> - 执行查询</span></li>
</ul>
</p>
</div>
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