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, $foreignID;
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 $dataClass The class of the DataObjects that this will list.
* @param $joinTable The name of the table whose entries define the content of this
* many_many relation.
* @param $localKey The key in the join table that maps to the dataClass' PK.
* @param $foreignKey The key in the join table that maps to joined class' PK.
* @param $extraFields A map of field => fieldtype of extra fields on the join table.
*/
function __construct($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, "\"$this->localKey\" = \"$baseClass\".\"ID\"");
// Query the extra fields from the join table
if($extraFields) $this->dataQuery->selectFromTable($joinTable, array_keys($extraFields));
}
/**
* Return a filter expression for the foreign ID.
*/
protected function foreignIDFilter() {
// Apply relation filter
if(is_array($this->foreignID)) {
return "\"$this->joinTable\".\"$this->foreignKey\" IN ('" .
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implode("', '", array_map('Convert::raw2sql', $this->foreignID)) . "')";
} else if($this->foreignID){
return "\"$this->joinTable\".\"$this->foreignKey\" = '" .
Convert::raw2sql($this->foreignID) . "'";
}
}
/**
* Add an item to this many_many relationship
* Does so by adding an entry to the joinTable.
* @param $extraFields A map of additional columns to insert into the joinTable
*/
function add($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 $this->dataClass object, or ID value", E_USER_ERROR);
// Validate foreignID
if(!$this->foreignID) {
throw new Exception("ManyManyList::add() can't be called until a foreign ID is set", E_USER_WARNING);
}
if(is_array($this->foreignID)) {
throw new Exception("ManyManyList::add() can't be called on a list linked to mulitple foreign IDs", E_USER_WARNING);
}
// Delete old entries, to prevent duplication
$this->removeById($itemID);
// Insert new entry
$manipulation = array();
$manipulation[$this->joinTable]['command'] = 'insert';
if($extraFields) foreach($extraFields as $k => $v) {
$manipulation[$this->joinTable]['fields'][$k] = "'" . Convert::raw2sql($v) . "'";
}
$manipulation[$this->joinTable]['fields'][$this->localKey] = $itemID;
$manipulation[$this->joinTable]['fields'][$this->foreignKey] = $this->foreignID;
DB::manipulate($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 $itemID The ID of the item to remove.
*/
function remove($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 $itemID The item it
*/
function removeByID($itemID) {
if(!is_numeric($itemID)) throw new InvalidArgumentException("ManyManyList::removeById() expecting an ID");
$query = new SQLQuery("*", array("\"$this->joinTable\""));
$query->delete = true;
if($filter = $this->foreignIDFilter()) {
$query->where($filter);
} else {
user_error("Can't call ManyManyList::remove() until a foreign ID is set", E_USER_WARNING);
}
$query->where("\"$this->localKey\" = {$itemID}");
$query->execute();
}
/**
* Remove all items from this many-many join. To remove a subset of items, filter it first.
*/
function removeAll() {
$query = $this->dataQuery()->query();
$query->delete = true;
$query->select = array('*');
$query->from = array("\"$this->joinTable\"");
$query->orderby = null;
$query->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 $childID The ID of the child for the relationship
* @return array Map of fieldName => fieldValue
*/
function getExtraData($componentName, $childID) {
$ownerObj = $this->ownerObj;
$parentField = $this->ownerClass . 'ID';
$childField = ($this->childClass == $this->ownerClass) ? 'ChildID' : ($this->childClass . 'ID');
$result = array();
if(!isset($componentName)) {
user_error('ComponentSet::getExtraData() passed a NULL component name', E_USER_ERROR);
}
if(!is_numeric($childID)) {
user_error('ComponentSet::getExtraData() passed a non-numeric child ID', E_USER_ERROR);
}
// @todo Optimize into a single query instead of one per extra field
if($this->extraFields) {
foreach($this->extraFields as $fieldName => $dbFieldSpec) {
$query = DB::query("SELECT \"$fieldName\" FROM \"$this->tableName\" WHERE \"$parentField\" = {$this->ownerObj->ID} AND \"$childField\" = {$childID}");
$value = $query->value();
$result[$fieldName] = $value;
}
}
return $result;
}
}