Attributes are the most atomic parts of a data model. They cannot be decomposed into lower level components. In a relational data model, an attribute cannot exist independently from an entity type. Accordingly all attributes are always identified and shown as part of entity types.
A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. For instance, a data model may specify that the data element representing a car be composed of a number of other elements which, in turn, represent the color and size of the car and define its owner.
A domain is a named type of data representation that may apply to one or more attributes.
An entity type is a representation of a person, place, thing, event or concept of interest to a retailer. Examples of entities include Customer, Item, Retail Store, Web Site, Purchase Order, Retail Transaction - and the list can go on to hundreds of nouns. Each entity type has a unique, singular noun phrase assigned as its name. In a relational data model, each entity type instance is uniquely identified by a primary key. A primary key is one or more attributes that have values used to uniquely identify and distinguish each entity type instance from each other.
Integrity rules are needed to inform the data models about certain constraints in the real world. Specific integrity rules apply to one domain. General integrity rules apply to all domains.
Minimum Logical Element (MLE)
It is the smallest possible unit of bundled items, that make logical sense to be combined together, viewed as business, designers and developers alike.
A relationship identifies, names and defines an association between two entity types.