Source of: /manual/en/internals2.pdo.pdo-stmt-t.php
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<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 programlisting"><br />
/* represents a prepared statement */<br />
struct _pdo_stmt_t {<br />
/* driver specifics */<br />
struct pdo_stmt_methods *methods; <a name="internals2.pdo.stmt.co.methods" id="internals2.pdo.stmt.co.methods">*</a><br />
void *driver_data; <a name="internals2.pdo.stmt.co.driver-data" id="internals2.pdo.stmt.co.driver-data">**</a><br />
<br />
/* if true, we've already successfully executed this statement at least<br />
* once */<br />
unsigned executed:1; <a name="internals2.pdo.stmt.co.executed" id="internals2.pdo.stmt.co.executed">***</a><br />
/* if true, the statement supports placeholders and can implement<br />
* bindParam() for its prepared statements, if false, PDO should<br />
* emulate prepare and bind on its behalf */<br />
unsigned supports_placeholders:2; <a name="internals2.pdo.stmt.co.holder" id="internals2.pdo.stmt.co.holder">****</a><br />
<br />
/* the number of columns in the result set; not valid until after<br />
* the statement has been executed at least once. In some cases, might<br />
* not be valid until fetch (at the driver level) has been called at least once.<br />
* */<br />
int column_count; <a name="internals2.pdo.stmt.co.colcount" id="internals2.pdo.stmt.co.colcount">*****</a><br />
struct pdo_column_data *columns; <a name="internals2.pdo.stmt.co.cols" id="internals2.pdo.stmt.co.cols">******</a><br />
<br />
/* points at the dbh that this statement was prepared on */<br />
pdo_dbh_t *dbh;<br />
<br />
/* keep track of bound input parameters. Some drivers support<br />
* input/output parameters, but you can't rely on that working */<br />
HashTable *bound_params;<br />
/* When rewriting from named to positional, this maps positions to names */<br />
HashTable *bound_param_map; <br />
/* keep track of PHP variables bound to named (or positional) columns<br />
* in the result set */<br />
HashTable *bound_columns;<br />
<br />
/* not always meaningful */<br />
long row_count;<br />
<br />
/* used to hold the statement's current query */<br />
char *query_string;<br />
int query_stringlen;<br />
<br />
/* the copy of the query with expanded binds ONLY for emulated-prepare drivers */<br />
char *active_query_string;<br />
int active_query_stringlen;<br />
<br />
/* the cursor specific error code. */<br />
pdo_error_type error_code;<br />
<br />
/* used by the query parser for driver specific<br />
* parameter naming (see pgsql driver for example) */<br />
const char *named_rewrite_template;<br />
};<br />
</div>
</div>
<table class="callout">
<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
<b>SKEL_handle_preparer()</b>.
</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 <b>SKEL_handle_factory()</b>)
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.php" class="xref">Fleshing out your skeleton</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
<b>SKEL_stmt_execute()</b> but with some database
implementations, the column count may not be available until
<b>SKEL_stmt_fetch()</b> has been called at least once.
Drivers that implement <b>SKEL_stmt_next_rowset()</b> 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
<b>SKEL_stmt_describe()</b>. You must set the
<i><tt class="parameter">precision</tt></i>
, <i><tt class="parameter">maxlen</tt></i>
,
<i><tt class="parameter">name</tt></i>
, <i><tt class="parameter">namelen</tt></i>
and
<i><tt class="parameter">param_type</tt></i>
members for each column.
The <i><tt class="parameter">name</tt></i>
is expected to be allocated using
<b>emalloc()</b>; PDO will call <b>efree()</b> at
the appropriate time.
</p>
</td></tr>
</table>
</div><?php manual_footer(); ?>
