silverstripe-framework/model/ManyManyList.php

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<?php
/**
* Subclass of {@link DataList} representing a many_many relation
*/
class ManyManyList extends RelationList {
protected $joinTable;
protected $localKey;
protected $foreignKey;
protected $extraFields;
/**
* Create a new ManyManyList object.
*
* A ManyManyList object represents a list of DataObject records that correspond to a many-many
* relationship. In addition to,
*
* Generation of the appropriate record set is left up to the caller, using the normal
* {@link DataList} methods. Addition arguments are used to support {@@link add()}
* and {@link remove()} methods.
*
* @param string $dataClass The class of the DataObjects that this will list.
* @param string $joinTable The name of the table whose entries define the content of this many_many relation.
* @param string $localKey The key in the join table that maps to the dataClass' PK.
* @param string $foreignKey The key in the join table that maps to joined class' PK.
* @param string $extraFields A map of field => fieldtype of extra fields on the join table.
*
* @example new ManyManyList('Group','Group_Members', 'GroupID', 'MemberID');
*/
public function __construct($dataClass, $joinTable, $localKey, $foreignKey, $extraFields = array()) {
parent::__construct($dataClass);
$this->joinTable = $joinTable;
$this->localKey = $localKey;
$this->foreignKey = $foreignKey;
$this->extraFields = $extraFields;
$baseClass = ClassInfo::baseDataClass($dataClass);
// Join to the many-many join table
$this->dataQuery->innerJoin($joinTable, "\"$joinTable\".\"$this->localKey\" = \"$baseClass\".\"ID\"");
// Query the extra fields from the join table
if($extraFields) $this->dataQuery->selectFromTable($joinTable, array_keys($extraFields));
}
/**
* Return a filter expression for when getting the contents of the relationship for some foreign ID
* @return string
*/
protected function foreignIDFilter($id = null) {
if ($id === null) $id = $this->getForeignID();
// Apply relation filter
if(is_array($id)) {
return "\"$this->joinTable\".\"$this->foreignKey\" IN ('" .
implode("', '", array_map('Convert::raw2sql', $id)) . "')";
} else if($id !== null){
return "\"$this->joinTable\".\"$this->foreignKey\" = '" .
Convert::raw2sql($id) . "'";
}
}
/**
* Return a filter expression for the join table when writing to the join table
*
* When writing (add, remove, removeByID), we need to filter the join table to just the relevant
* entries. However some subclasses of ManyManyList (Member_GroupSet) modify foreignIDFilter to
* include additional calculated entries, so we need different filters when reading and when writing
*
* @return string
*/
protected function foreignIDWriteFilter($id = null) {
return $this->foreignIDFilter($id);
}
/**
* Add an item to this many_many relationship
* Does so by adding an entry to the joinTable.
* @param $extraFields A map of additional columns to insert into the joinTable
*/
public function add($item, $extraFields = null) {
if(is_numeric($item)) $itemID = $item;
else if($item instanceof $this->dataClass) $itemID = $item->ID;
else {
throw new InvalidArgumentException("ManyManyList::add() expecting a $this->dataClass object, or ID value",
E_USER_ERROR);
}
$foreignIDs = $this->getForeignID();
$foreignFilter = $this->foreignIDWriteFilter();
// Validate foreignID
if(!$foreignIDs) {
throw new Exception("ManyManyList::add() can't be called until a foreign ID is set", E_USER_WARNING);
}
if($foreignFilter) {
$query = new SQLQuery("*", array("\"$this->joinTable\""));
$query->setWhere($foreignFilter);
$hasExisting = ($query->count() > 0);
} else {
$hasExisting = false;
}
// Insert or update
foreach((array)$foreignIDs as $foreignID) {
$manipulation = array();
if($hasExisting) {
$manipulation[$this->joinTable]['command'] = 'update';
$manipulation[$this->joinTable]['where'] = "\"$this->joinTable\".\"$this->foreignKey\" = " .
"'" . Convert::raw2sql($foreignID) . "'" .
" AND \"$this->localKey\" = {$itemID}";
} else {
$manipulation[$this->joinTable]['command'] = 'insert';
}
if($extraFields) foreach($extraFields as $k => $v) {
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if(is_null($v)) $manipulation[$this->joinTable]['fields'][$k] = 'NULL';
else $manipulation[$this->joinTable]['fields'][$k] = "'" . Convert::raw2sql($v) . "'";
}
$manipulation[$this->joinTable]['fields'][$this->localKey] = $itemID;
$manipulation[$this->joinTable]['fields'][$this->foreignKey] = $foreignID;
DB::manipulate($manipulation);
}
}
/**
* Remove the given item from this list.
* Note that for a ManyManyList, the item is never actually deleted, only the join table is affected
* @param $itemID The ID of the item to remove.
*/
public function remove($item) {
if(!($item instanceof $this->dataClass)) {
throw new InvalidArgumentException("ManyManyList::remove() expecting a $this->dataClass object");
}
return $this->removeByID($item->ID);
}
/**
* Remove the given item from this list.
* Note that for a ManyManyList, the item is never actually deleted, only the join table is affected
* @param $itemID The item it
*/
public function removeByID($itemID) {
if(!is_numeric($itemID)) throw new InvalidArgumentException("ManyManyList::removeById() expecting an ID");
$query = new SQLQuery("*", array("\"$this->joinTable\""));
$query->setDelete(true);
if($filter = $this->foreignIDWriteFilter($this->getForeignID())) {
$query->setWhere($filter);
} else {
user_error("Can't call ManyManyList::remove() until a foreign ID is set", E_USER_WARNING);
}
$query->addWhere("\"$this->localKey\" = {$itemID}");
$query->execute();
}
/**
* Remove all items from this many-many join. To remove a subset of items, filter it first.
*/
public function removeAll() {
$base = ClassInfo::baseDataClass($this->dataClass());
// Remove the join to the join table to avoid MySQL row locking issues.
$query = $this->dataQuery();
$query->removeFilterOn($query->getQueryParam('Foreign.Filter'));
$query = $query->query();
$query->setSelect("\"$base\".\"ID\"");
$from = $query->getFrom();
unset($from[$this->joinTable]);
$query->setFrom($from);
// Use a sub-query as SQLite does not support setting delete targets in
// joined queries.
$delete = new SQLQuery();
$delete->setDelete(true);
$delete->setFrom("\"$this->joinTable\"");
$delete->addWhere($this->foreignIDFilter());
$delete->addWhere("\"$this->joinTable\".\"$this->localKey\" IN ({$query->sql()})");
$delete->execute();
}
/**
* Find the extra field data for a single row of the relationship
* join table, given the known child ID.
*
* @todo Add tests for this / refactor it / something
*
* @param string $componentName The name of the component
* @param int $itemID The ID of the child for the relationship
* @return array Map of fieldName => fieldValue
*/
function getExtraData($componentName, $itemID) {
$result = array();
if(!is_numeric($itemID)) {
user_error('ComponentSet::getExtraData() passed a non-numeric child ID', E_USER_ERROR);
}
// @todo Optimize into a single query instead of one per extra field
if($this->extraFields) {
foreach($this->extraFields as $fieldName => $dbFieldSpec) {
$query = new SQLQuery("\"$fieldName\"", array("\"$this->joinTable\""));
if($filter = $this->foreignIDWriteFilter($this->getForeignID())) {
$query->setWhere($filter);
} else {
user_error("Can't call ManyManyList::getExtraData() until a foreign ID is set", E_USER_WARNING);
}
$query->addWhere("\"$this->localKey\" = {$itemID}");
$result[$fieldName] = $query->execute()->value();
}
}
return $result;
}
/**
* Gets the join table used for the relationship.
*
* @return string the name of the table
*/
public function getJoinTable() {
return $this->joinTable;
}
/**
* Gets the key used to store the ID of the local/parent object.
*
* @return string the field name
*/
public function getLocalKey() {
return $this->localKey;
}
/**
* Gets the key used to store the ID of the foreign/child object.
*
* @return string the field name
*/
public function getForeignKey() {
return $this->foreignKey;
}
/**
* Gets the extra fields included in the relationship.
*
* @return array a map of field names to types
*/
public function getExtraFields() {
return $this->extraFields;
}
}