db_rewrite_sql
Definition
db_rewrite_sql($query, $primary_table = 'n', $primary_field = 'nid', $args = array())
drupal/includes/database.inc, line 236
Description
Rewrites node queries.
Parameters
$query Query to be rewritten.
$primary_table Name or alias of the table which has the primary key field for this query. Possible values are: comments, forum, node, term_data, vocabulary.
$primary_field Name of the primary field.
$args An array of arguments, passed to the implementations of hook_db_rewrite_sql.
Return value
The original query with JOIN and WHERE statements inserted from hook_db_rewrite_sql implementations. nid is rewritten if needed.
Related topics
Name | Description |
|---|---|
| Database abstraction layer | Allow the use of different database servers using the same code base. |
Code
function db_rewrite_sql($query, $primary_table = 'n', $primary_field = 'nid', $args = array()) {
list($join, $where, $distinct) = _db_rewrite_sql($query, $primary_table, $primary_field, $args);
if ($distinct) {
$field_to_select = 'DISTINCT('. $primary_table .'.'. $primary_field .')';
// (?<!text) is a negative look-behind (no need to rewrite queries that already use DISTINCT).
$query = preg_replace('/(SELECT.*)('. $primary_table .'\.)?(?<!DISTINCT\()(?<!DISTINCT\('. $primary_table .'\.)'. $primary_field .'(.*FROM)/AUsi', '\1'. $field_to_select .'\3', $query);
}
if (!empty($join)) {
$query = preg_replace('|FROM[^[:upper:]/,]+|','\0 '. $join .' ', $query);
}
if (!empty($where)) {
if (strpos($query, 'WHERE')) {
$replace = 'WHERE';
$add = 'AND';
}
elseif (strpos($query, 'GROUP')) {
$replace = 'GROUP';
$add = 'GROUP';
}
elseif (strpos($query, 'ORDER')) {
$replace = 'ORDER';
$add = 'ORDER';
}
elseif (strpos($query, 'LIMIT')) {
$replace = 'LIMIT';
$add = 'LIMIT';
}
else {
$query .= ' WHERE '. $where;
}
if (isset($replace)) {
$query = str_replace($replace, 'WHERE '. $where .' '. $add .' ', $query);
}
}
return $query;
}