Entity–attribute–value model (EAV) is a data model to describe entities where the number of attributes (properties, parameters) that can be used to describe them is potentially vast, but the number that will actually apply to a given entity is relatively modest. In mathematics, this model is known as a sparse matrix. EAV is also known as object–attribute–value model, vertical database model and open schema.
Hierarchie (insgesamt 147 Klassen)
By decoupling the logical Model and the code that talks to the database,
it's theoretically possible to write new resource classes for a different
database schemas and platforms while keeping your Models themselves untouched.
Load entity’s attributes into the object
Save entity’s attributes into the object’s resource
|Load||Join relevant tables together, then passing data to the object||Save to multiple tables|
|Save||Direct select from database||Save to unique table|
Use a setup script to add a catalog/product select attribute using the Magento eav/entity_attribute_source_table. Also add some options
Add a customer/customer multiselect attribute using a customer source and backend model. Make it possible to unset all options for that attribute on customers using the Admin interface.
Add a catalog/product select attribute with a custom source model that is indexed by the flat table indexer, and that also works in the layered navigation.
Use a backend model to set the associated page and store_id entity properties.
Create an uninstall script (which would need to be run manually) from the comments module that leaves Magento in a state as if the module had never been installed.