Logical data model assets

Logical data models capture the business definition of information assets by using the entity-relationship modeling approach. The logical data model consists of a set of related entities and their business associations.

Logical data models can be implemented by both physical data models and database schemas. You can use InfoSphere® Metadata Asset Manager to set implementation relationships between logical data models, physical data models, database schemas, and their contained assets.

You can use bridges to import logical data models from design tools such as InfoSphere Data Architect and CA ERwin Data Modeler.

If you import logical data models, you have an end-to-end view of the metadata assets that control data flow. You can trace a logical entity to the table that implements the logical entity, through the jobs that use the columns of the table, and on to the business intelligence (BI) report that is based on the table.

Asset types

The following table lists and defines the types of logical data model assets that are stored in the metadata repository.

Table 1. Logical data model assets
Asset type	Definition	Components of the identity of the asset	Contained asset types
Logical data model	A logical representation of the data objects that are related to a business domain and the rules or constraints that govern their associations in real-world applications. Logical data models consist of a set of entities and relationships. A logical data model can be implemented by a physical data model or a database schema.	Logical data model name Logical data model namespace: a value that you set during import to help uniquely identify the model If a logical data model has a submodel, the identity components of the submodel are the following: Name of the contained logical data model Namespace of the contained logical data model Identity of the containing logical data model	Subject area, logical entity, logical relationship, entity generalization hierarchy, and logical domain Note: Logical data models can also contain submodels.
Subject area	A grouping of related logical entities that focus on a particular business area. A logical entity can be included in more than one subject area to better differentiate it from other logical entities in the logical data model.	Subject area name Identity of the logical data model	A subject area can include but does not contain logical entities, logical relationships, and entity generalization hierarchies. Deleting the subject area does not delete assets of these types.
Logical entity	An asset that represents the data structure in the logical data model. A logical entity defines entity attributes, entity keys, and entity constraints. A logical entity can be implemented by a design table in a physical model or by a database table.	Logical entity name Identity of the logical data model	Entity attribute, entity key, and entity constraint
Entity attribute	A relevant property or characteristic of an entity that defines the meaning and purpose of a unit of data. An entity attribute can be implemented by a design column in a physical data model or by a database column.	Entity attribute name Identity of the logical entity	Validation constraint
Validation constraint	A validation constraint is an abstract supertype that can be a validation rule, validation range, or validation list.	See validation rule, validation range, or validation list.
Validation rule	An expression that defines the valid values for an entity attribute or a logical domain.	Validation rule name Validation rule name qualifier Identity of the logical data model
Validation range	A range of values that defines the valid values for an entity attribute or a logical domain.	Validation range name Validation range name qualifier Identity of the logical data model
Validation list	A list of discrete values that defines the valid values for an entity attribute or a logical domain.	Validation list name Validation list name qualifier Identity of the logical data model	Validation value
Validation value	A discrete value in a validation list.	Validation value name Validation value sequence Identity of the validation list
Entity key	A semantic identifier that consists of one or more entity attributes. An entity key is an abstract supertype that can be a unique key, a reference key, or an inversion entry.	See unique key, reference key, or inversion key.
Unique key	A key that specifies the values of the entity attributes that uniquely identify the instances of the logical entity. A unique key can be implemented as a candidate key in a design table or a database table.	Unique key name Identity of the logical entity
Reference key	A key that specifies a referential integrity constraint that is associated with a relationship. A reference key can be implemented as a foreign key in a design table or a database table.	Reference key name Identity of the logical entity
Inversion key	A non-unique logical identifier that defines an inversion entry. An inversion key can be implemented by an index in a design table or a database table.	Inversion key name Identity of the logical entity
Entity key component	An association between an entity key and one of its attributes.	Identity of the entity key Identity of the entity attribute
Entity constraint	A business rule in the form of a constraint that is attached to a logical entity.	Entity constraint name Identity of the logical entity
Logical relationship	An asset that represents the set of business rules that define the associations between two logical entities. A logical relationship can be implemented by a design foreign key or a foreign key for a database table.	Logical relationship name Identity of the child entity of the relationship Identity of the parent entity of the relationship	Relationship end
Relationship end	A connection between the entity and the relationship that expresses how the logical entity participates in the relationship.	Name of the relationship end Identity of the relationship Identity of the logical entity that is referenced by the relationship end
Entity generalization hierarchy	An asset that represents the inheritance associations that classify logical entities into subtypes and supertypes. A hierarchy supertype is a logical entity that is the supertype or parent entity in the hierarchy.	Name of the entity generalization hierarchy Identity of the parent entity Identity of the logical model	Hierarchy supertype and hierarchy subtype
Hierarchy subtype	An asset that connects a logical entity as a subtype in an entity generalization hierarchy. An entity can be a subtype in more than one hierarchy.	Name of the hierarchy subtype Identity of the entity generalization hierarchy Identity of the logical entity that is the subtype
Logical domain	A user-defined data type or global attribute that can be reused in multiple logical entities. A logical domain can be implemented by a physical domain or a database domain. Logical domains can contain other logical domains.	Logical domain name Logical domain name qualifier Identity of the logical data model If a logical domain contains another logical domain, the identity components of the contained logical domain are the following: Name of the contained logical domain Identity of the containing logical domain	Logical domain