EAV (Entity-Attribute-Value)
EAV is a database pattern that stores attributes as rows instead of columns — flexible, but heavy to query.
Entity-Attribute-Value (EAV) is a schema design where each attribute of an object is stored as its own row (entity, attribute name, value) rather than as a column. It gives platforms like Magento enormous flexibility to add product attributes without schema changes — but it makes reporting painful, because a single product view can require many self-joins. Running those joins on a cloned analytical database, rather than your live store, keeps the flexibility without the production performance cost.