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</div><hr /><div id="internals2.pdo.pdo-stmt-t" class="sect1">
<h2 class="title">pdo_stmt_t definition</h2>
<p class="para">
All fields should be treated as read-only unless explicitly stated
otherwise.
</p>
<div class="figure">
<h1 class="title">pdo_stmt_t</h1>
<div class="example-contents"><div class="ccode"><pre class="ccode">/* represents a prepared statement */
struct _pdo_stmt_t {
/* driver specifics */
struct pdo_stmt_methods *methods;</pre>
</div><a name="internals2.pdo.stmt.co.methods" id="internals2.pdo.stmt.co.methods">*</a><div class="ccode"><pre class="ccode">void *driver_data;</pre>
</div><a name="internals2.pdo.stmt.co.driver-data" id="internals2.pdo.stmt.co.driver-data">**</a><div class="ccode"><pre class="ccode">/* if true, we've already successfully executed this statement at least
* once */
unsigned executed:1;</pre>
</div><a name="internals2.pdo.stmt.co.executed" id="internals2.pdo.stmt.co.executed">***</a><div class="ccode"><pre class="ccode">/* if true, the statement supports placeholders and can implement
* bindParam() for its prepared statements, if false, PDO should
* emulate prepare and bind on its behalf */
unsigned supports_placeholders:2;</pre>
</div><a name="internals2.pdo.stmt.co.holder" id="internals2.pdo.stmt.co.holder">****</a><div class="ccode"><pre class="ccode">/* the number of columns in the result set; not valid until after
* the statement has been executed at least once. In some cases, might
* not be valid until fetch (at the driver level) has been called at least once.
* */
int column_count;</pre>
</div><a name="internals2.pdo.stmt.co.colcount" id="internals2.pdo.stmt.co.colcount">*****</a><div class="ccode"><pre class="ccode">struct pdo_column_data *columns;</pre>
</div><a name="internals2.pdo.stmt.co.cols" id="internals2.pdo.stmt.co.cols">******</a><div class="ccode"><pre class="ccode">/* points at the dbh that this statement was prepared on */
pdo_dbh_t *dbh;
/* keep track of bound input parameters. Some drivers support
* input/output parameters, but you can't rely on that working */
HashTable *bound_params;
/* When rewriting from named to positional, this maps positions to names */
HashTable *bound_param_map;
/* keep track of PHP variables bound to named (or positional) columns
* in the result set */
HashTable *bound_columns;
/* not always meaningful */
long row_count;
/* used to hold the statement's current query */
char *query_string;
int query_stringlen;
/* the copy of the query with expanded binds ONLY for emulated-prepare drivers */
char *active_query_string;
int active_query_stringlen;
/* the cursor specific error code. */
pdo_error_type error_code;
/* used by the query parser for driver specific
* parameter naming (see pgsql driver for example) */
const char *named_rewrite_template;
};</pre>
</div></div>
</div>
<table>
<tr><td><a href="#internals2.pdo.stmt.co.methods">*</a></td><td>
<p class="para">
The driver <em class="emphasis">must</em> set this during
<span class="function"><strong>SKEL_handle_preparer()</strong></span>.
</p>
</td></tr>
<tr><td><a href="#internals2.pdo.stmt.co.driver-data">**</a></td><td>
<p class="para">
This item is for use by the driver; the intended usage is to store a
pointer (during <span class="function"><strong>SKEL_handle_factory()</strong></span>)
to whatever instance data is required to maintain a connection to
the database.
</p>
</td></tr>
<tr><td><a href="#internals2.pdo.stmt.co.executed">***</a></td><td>
<p class="para">
This is set by PDO after the statement has been executed for the first
time. Your driver can inspect this value to determine if it can skip
one-time actions as an optimization.
</p>
</td></tr>
<tr><td><a href="#internals2.pdo.stmt.co.holder">****</a></td><td>
<p class="para">
Discussed in more detail in <a href="internals2.pdo.implementing.html#internals2.pdo.preparer" class="xref">SKEL_handle_preparer</a>.
</p>
</td></tr>
<tr><td><a href="#internals2.pdo.stmt.co.colcount">*****</a></td><td>
<p class="para">
Your driver is responsible for setting this field to the number of
columns available in a result set. This is usually set during
<span class="function"><strong>SKEL_stmt_execute()</strong></span> but with some database
implementations, the column count may not be available until
<span class="function"><strong>SKEL_stmt_fetch()</strong></span> has been called at least once.
Drivers that implement <span class="function"><strong>SKEL_stmt_next_rowset()</strong></span> should
update the column count when a new rowset is available.
</p>
</td></tr>
<tr><td><a href="#internals2.pdo.stmt.co.cols">******</a></td><td>
<p class="para">
PDO will allocate this field based on the value that you set for the
column count. You are responsible for populating each column during
<span class="function"><strong>SKEL_stmt_describe()</strong></span>. You must set the
<em><code class="parameter">precision</code></em>, <em><code class="parameter">maxlen</code></em>,
<em><code class="parameter">name</code></em>, <em><code class="parameter">namelen</code></em> and
<em><code class="parameter">param_type</code></em> members for each column.
The <em><code class="parameter">name</code></em> is expected to be allocated using
<span class="function"><strong>emalloc()</strong></span>; PDO will call <span class="function"><strong>efree()</strong></span> at
the appropriate time.
</p>
</td></tr>
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