Short for entity-relationship-attribute model. A model of a set of data items and relationships between them in terms of the entities, relationships, and attributes involved.
Entities have attributes and have relationships with other entities. They have an entity name; usually names are required to be unique. Entities are often implemented as a record comprising a number of fields.
Attributes are usually represented in a data dictionary and describe the characteristic features of the entity. Each attribute is named; usually names of attributes are required to be unique. Attributes are often implemented as fields with values.
Each relationship has two names (a forward and a reverse name); usually relationship names are required to be unique. There can be more than one relationship between a pair of entities.
See also ERA diagram.