Collection in magento

Here, I am going to explain some database interaction functions present in the class Mage_Eav_Model_Entity_Collection_Abstract. These collection functions are very useful to select data from Magento database. We need them almost all the time for filtering collection object.


Below are some of the useful functions that we use most often.

Class: Mage_Eav_Model_Entity_Collection_Abstract

addAttributeToFilter: adds WHERE clause on $attribute specified by $condition

/**
* Add attribute filter to collection
*
* If $attribute is an array will add OR condition with following format:
* array(
* array(‘attribute’=>’firstname’, ‘like’=>’test%’),
* array(‘attribute’=>’lastname’, ‘like’=>’test%’),
* )
*
* @see self::_getConditionSql for $condition
* @param Mage_Eav_Model_Entity_Attribute_Interface|integer|string|array $attribute
* @param null|string|array $condition
* @param string $operator
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
addAttributeToFilter($attribute, $condition=null, $joinType=’inner’)

addAttributeToSelect: gets the value for $attribute in the SELECT clause; specify * to get all attributes (i.e. to execute SELECT *)

/**
* Add attribute to entities in collection
*
* If $attribute==’*’ select all attributes
*
* @param array|string|integer|Mage_Core_Model_Config_Element $attribute
* @param false|string $joinType flag for joining attribute
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
addAttributeToSelect($attribute, $joinType=false)

If an array is passed but no attribute code specified, it will be interpreted as a group of OR conditions that will be processed in the same way.
If no attribute code is specified, it defaults to eq.

$collection = Mage::getModel('catalog/product')->getCollection();

// select all attributes
$collection->addAttributeToSelect('*');

// select specific attributes
$collection->addAttributeToSelect(array('name', 'url_key', 'type_id'));

// select only those items whose status = 1
$collection->addAttributeToFilter('status', 1);

// alternative to select only those items whose status = 1
$collection->addAttributeToFilter('status', array('eq' => 1));

// using LIKE statement
$collection->addAttributeToFilter('sku', array('like' => '%CH%'));

// using IN statement,
// i.e. selecting only those items whose ID fall in the given array
$collection->addAttributeToFilter('id', array('in' => array(1, 14, 51, 52)));

// selecting only those items whose ID is greater than the given value
$collection->addAttributeToFilter('id', array('gt' => 5));

// select by date range
$collection->addAttributeToFilter('date_field', array(
    'from' => '10 September 2010',
    'from' => '21 September 2010',
    'date' => true, // specifies conversion of comparison values
    ));

// Add OR condition:
$collection->addAttributeToFilter(array(
    array(
        'attribute' => 'field_name',
        'in'        => array(1, 2, 3),
        ),
    array(
        'attribute' => 'date_field',
        'from'      => '2010-09-10',
        ),
    ));
Below is the full filter condition codes with attribute code and its sql equivalent

eq : =
neq : !=
like : LIKE
nlike : NOT LIKE
in : IN ()
nin : NOT IN ()
is : IS
notnull : IS NOT NULL
null : IS NULL
moreq : >=
gt : >
lt : <
gteq : >=
lteq : <=
finset : FIND_IN_SET()
from : >= (for use with dates)
to : <= (for use with dates)
date : optional flag for use with from/to to specify that comparison value should first be converted to a date
datetime : optional flag for use with from/to to specify that comparison value should first be converted to a datetime

addFieldToFilter: alias for addAttributeToFilter(). This filters the database table fields.

/**
* Wrapper for compatibility with Varien_Data_Collection_Db
*
* @param mixed $attribute
* @param mixed $condition
*/
addFieldToFilter($attribute, $condition=null)

addAttributeToSort: adds ORDER BY clause on $attribute

/**
* Add attribute to sort order
*
* @param string $attribute
* @param string $dir
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
addAttributeToSort($attribute, $dir=’asc’)

addExpressionAttributeToSelect: adds SQL expression $expression, using $alias, to SELECT clause (typically containing aggregate functions such as SUM(), COUNT()); when $attribute specifies a single attribute as a string, $expression can reference the attribute as simply {{attribute}}, but when passing an array of attributes, each attribute must be referenced in $expression by the name of the specific attribute;

/**
* Add attribute expression (SUM, COUNT, etc)
*
* Example: (‘sub_total’, ‘SUM({{attribute}})’, ‘revenue’)
* Example: (‘sub_total’, ‘SUM({{revenue}})’, ‘revenue’)
*
* For some functions like SUM use groupByAttribute.
*
* @param string $alias
* @param string $expression
* @param string $attribute
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
addExpressionAttributeToSelect($alias, $expression, $attribute)

groupByAttribute: adds $attribute to GROUP BY clause

/**
* Groups results by specified attribute
*
* @param string|array $attribute
*/
groupByAttribute($attribute)

joinAttribute: joins another entity and adds attribute from joined entity, using $alias, to SELECT clause.

Here are the parameters for joinAttribute function:-

$alias = selected field name. You can keep it’s name whatever you want.

$attribute = joined entity type code and attribute code = entity_type_code/attribute_code
entity_type_code is present in eav_entity_type table
attribute_code is present in eav_attribute table
attribute_code is attribute of the corresponding entity you want to select out.

$bind = attribute code of the main entity to link to the joined entity.

$filter = primary key for the joined entity (entity_id default)

/**
* Add attribute from joined entity to select
*
* Examples:
* (‘billing_firstname’, ‘customer_address/firstname’, ‘default_billing’)
* (‘billing_lastname’, ‘customer_address/lastname’, ‘default_billing’)
* (‘shipping_lastname’, ‘customer_address/lastname’, ‘default_billing’)
* (‘shipping_postalcode’, ‘customer_address/postalcode’, ‘default_shipping’)
* (‘shipping_city’, $cityAttribute, ‘default_shipping’)
*
* Developer is encouraged to use existing instances of attributes and entities
* After first use of string entity name it will be cached in the collection
*
* @todo connect between joined attributes of same entity
* @param string $alias alias for the joined attribute
* @param string|Mage_Eav_Model_Entity_Attribute_Abstract $attribute
* @param string $bind attribute of the main entity to link with joined $filter
* @param string $filter primary key for the joined entity (entity_id default)
* @param string $joinType inner|left
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
joinAttribute($alias, $attribute, $bind, $filter=null, $joinType=’inner’, $storeId=null)

joinTable: joins table $table

Here are the parameters of the function joinTable:-

$table = table name to join
$bind = ( parent_key = foreign_key )
$fields = array of fields to select
$cond = where condition
$joinType = join type

/**
* Join a table
*
* @param string|array $table
* @param string $bind
* @param string|array $fields
* @param null|array $cond
* @param string $joinType
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
joinTable($table, $bind, $fields=null, $cond=null, $joinType=’inner’)

Using joinAttribute and joinTable

In the code below, all order invoice items are selected, i.e. all products that have been invoiced.
joinTable is used to join sales_order_entity table to fetch increment_id and store_id of the invoice for each product.
joinAttribute is used to fetch order_id, product_name, and store_id.
joinTable is used again to fetch the order status of each invoice item.

$collection = Mage::getModel('sales/order_invoice_item')
                    ->getCollection()
                    ->joinTable('sales_order_entity', 'entity_id=parent_id', array('invoice_id'=>'increment_id', 'store_id' => 'store_id'), null , 'left')
                    ->joinAttribute('order_id', 'invoice/order_id', 'parent_id', null, 'left')
                    ->joinAttribute('product_name', 'invoice_item/name', 'entity_id', null, 'left')
                    ->joinAttribute('store_id', 'invoice/store_id', 'parent_id', null, 'left')

                    ->joinTable('sales_order', 'entity_id=order_id', array('order_status'=>'status'), null , 'left')
                    ;
joinField: joins regular table field using an attribute as foreign key

/**
* Join regular table field and use an attribute as fk
*
* Examples:
* (‘country_name’, ‘directory/country_name’, ‘name’, ‘country_id=shipping_country’, “{{table}}.language_code=’en’”, ‘left’)
*
* @param string $alias ‘country_name’
* @param string $table ‘directory/country_name’
* @param string $field ‘name’
* @param string $bind ‘PK(country_id)=FK(shipping_country_id)’
* @param string|array $cond “{{table}}.language_code=’en’” OR array(‘language_code’=>’en’)
* @param string $joinType ‘left’
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
joinField($alias, $table, $field, $bind, $cond=null, $joinType=’inner’)

removeAttributeToSelect: removes $attribute from SELECT clause; specify null to remove all attributes

/**
* Remove an attribute from selection list
*
* @param string $attribute
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
removeAttributeToSelect($attribute=null)

setPage: sets LIMIT clause by specifying page number (one-indexed) and number of records per page; equivalent to calling setCurPage($pageNum) and setPageSize($pageSize)

/**
* Set collection page start and records to show
*
* @param integer $pageNum
* @param integer $pageSize
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
setPage($pageNum, $pageSize)

importFromArray: imports 2D array into collection as objects

/**
* Import 2D array into collection as objects
*
* If the imported items already exist, update the data for existing objects
*
* @param array $arr
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
importFromArray($arr)

exportToArray: returns collection data as a 2D array

/**
* Get collection data as a 2D array
*
* @return array
*/
exportToArray()

setOrder: alias for addAttributeToSort() q.v., identical except that it can accept array of attributes, and default $dir is desc

/**
* Set sorting order
*
* $attribute can also be an array of attributes
*
* @param string|array $attribute
* @param string $dir
* @return Mage_Eav_Model_Entity_Collection_Abstract
*/
setOrder($attribute, $dir=’desc’)