Interface: PreparedStatement  - X-Ref

Interface for a pre-compiled SQL statement.

Many drivers do not take advantage of pre-compiling SQL statements; for these
cases the precompilation is emulated.  This emulation comes with slight penalty involved
in parsing the queries, but provides other benefits such as a cleaner object model and ability
to work with BLOB and CLOB values w/o needing special LOB-specific routines.

This class is abstract because there are driver-specific implementations in [clearly] how queries
are executed, and how parameters are bound.

This class is not as abstract as the JDBC version.  For exmple, if you are using a driver
that uses name-based query param substitution, then you'd better bind your variables to
names rather than index numbers.  e.g. in Oracle
<code>
$stmt = $conn->prepareStatement("INSERT INTO users (name, passwd) VALUES (:name, :pass)");
$stmt->setString(":name", $name);
$stmt->executeUpdate();
</code>

Developer note:  In many ways this interface is an extension of the Statement interface.  However, due
to limitations in PHP5's interface extension model (specifically that you cannot change signatures on
methods defined in parent interface), we cannot extend the Statement interface.