1 views_plugin_query_default.inc | views_plugin_query_default::ensure_table($table, $relationship = NULL, $join = NULL) |
Ensure a table exists in the queue; if it already exists it won't do anything, but if it doesn't it will add the table queue. It will ensure a path leads back to the relationship table.
Parameters
$table: The unaliased name of the table to ensure.
$relationship: The relationship to ensure the table links to. Each relationship will get a unique instance of the table being added. If not specified, will be the primary table.
views_join $join: A views_join object (or derived object) to join the alias in.
Return value
The alias used to refer to this specific table, or NULL if the table: cannot be ensured.
File
- core/
modules/ views/ plugins/ views_plugin_query_default.inc, line 541 - Defines the default query object.
Class
- views_plugin_query_default
- Object used to create a SELECT query.
Code
function ensure_table($table, $relationship = NULL, $join = NULL) {
// ensure a relationship
if (empty($relationship)) {
$relationship = $this->base_table;
}
// If the relationship is the primary table, this actually be a relationship
// link back from an alias. We store all aliases along with the primary table
// to detect this state, because eventually it'll hit a table we already
// have and that's when we want to stop.
if ($relationship == $this->base_table && !empty($this->tables[$relationship][$table])) {
return $this->tables[$relationship][$table]['alias'];
}
if (!array_key_exists($relationship, $this->relationships)) {
return FALSE;
}
if ($table == $this->relationships[$relationship]['base']) {
return $relationship;
}
// If we do not have join info, fetch it.
if (!isset($join)) {
$join = $this->get_join_data($table, $this->relationships[$relationship]['base']);
}
// If it can't be fetched, this won't work.
if (empty($join)) {
return;
}
// Adjust this join for the relationship, which will ensure that the 'base'
// table it links to is correct. Tables adjoined to a relationship
// join to a link point, not the base table.
$join = $this->adjust_join($join, $relationship);
if ($this->ensure_path($table, $relationship, $join)) {
// Attempt to eliminate redundant joins. If this table's
// relationship and join exactly matches an existing table's
// relationship and join, we do not have to join to it again;
// just return the existing table's alias. See
// http://groups.drupal.org/node/11288 for details.
//
// This can be done safely here but not lower down in
// queue_table(), because queue_table() is also used by
// add_table() which requires the ability to intentionally add
// the same table with the same join multiple times. For
// example, a view that filters on 3 taxonomy terms using AND
// needs to join taxonomy_term_data 3 times with the same join.
// scan through the table queue to see if a matching join and
// relationship exists. If so, use it instead of this join.
// TODO: Scanning through $this->table_queue results in an
// O(N^2) algorithm, and this code runs every time the view is
// instantiated (Views 2 does not currently cache queries).
// There are a couple possible "improvements" but we should do
// some performance testing before picking one.
foreach ($this->table_queue as $queued_table) {
// In PHP 4 and 5, the == operation returns TRUE for two objects
// if they are instances of the same class and have the same
// attributes and values.
if ($queued_table['relationship'] == $relationship && $queued_table['join'] == $join) {
return $queued_table['alias'];
}
}
return $this->queue_table($table, $relationship, $join);
}
}