Name

prepare_cached

Synopsis

$sth = $dbh->prepare_cached($statement)
$sth = $dbh->prepare_cached($statement, \%attr)
$sth = $dbh->prepare_cached($statement, \%attr, $allow_active)

Like prepare except that the statement handle returned will be stored in a hash associated with the $dbh. If another call is made to prepare_cached with the same $statement and %attr values, then the corresponding cached $sth will be returned without contacting the database server.

This caching can be useful in some applications, but it can also cause problems and should be used with care. A warning will be generated if the cached $sth being returned is active (i.e., it is a SELECT that may still have data to be fetched). This warning can be suppressed by setting $allow_active to true. The cache can be accessed (and cleared) via the CachedKids attribute.

Here’s an example of one possible use of prepare_cached:

while ( ($field, $value) = each %search_fields ) {
    push @sql,   "$field = ?";
    push @values, $value;
}
$qualifier = "";
$qualifier = "where ".join(" and ", @sql) if @sql;
$sth = $dbh->prepare_cached("SELECT * FROM table $qualifier");
$sth->execute(@values);