Entity Relationship Modeling
Entity Relationship Modeling Glossary & Technical Reference
A reference glossary of key terms, modeling concepts, and acronyms used in Entity Relationship Modeling.
A
Attribute
A property or characteristic that describes an entity.
Attribute Domain
The permitted set, range, or format of values for an attribute.
C
Cardinality
The number of entity instances that can participate in a relationship.
Conceptual Data Model
A high-level representation of major business entities and relationships without implementation-specific detail.
E
Entity
A distinct business object or concept represented in the model.
Entity Identifier
An attribute or combination of attributes used to uniquely identify an entity instance.
Entity Relationship Diagram
A visual representation of entities, attributes, and relationships.
Entity Relationship Modeling
The process of identifying entities, attributes, and relationships to create a structured data model.
F
Foreign Key
An attribute or set of attributes referencing an identifier in another entity.
L
Logical Data Model
A detailed model defining entities, attributes, identifiers, and relationships while remaining relatively independent of physical implementation.
M
Many-to-Many Relationship
A relationship in which multiple instances of each entity can be associated with multiple instances of the other.
O
Optionality
Whether participation in a relationship is required or optional.
P
Primary Key
An attribute or combination of attributes that uniquely identifies an entity instance.
R
Recursive Relationship
A relationship in which an entity is related to another instance of the same entity.
Relationship
A meaningful association between two or more entities.
Relationship Attribute
An attribute that describes an association between entities rather than an entity itself.
S
Supertype
A generalized entity containing characteristics shared by more-specific entity types.
Subtype
A specialized entity extending or inheriting characteristics from a more general entity.
T
Ternary Relationship
A relationship involving three entity types simultaneously.
U
Unique Constraint
A rule requiring values or combinations of values to remain unique.
W
Weak Entity
An entity whose identification depends partly or fully on its relationship with another entity.
Key Modeling Concepts
One-to-One
Each instance of one entity is associated with at most one instance of another.
One-to-Many
One entity instance can be associated with multiple instances of another.
Many-to-Many
Multiple instances of each entity can be associated with multiple instances of the other.
Entity Integrity
Identifiers should uniquely and reliably identify entity instances.
Referential Integrity
Relationships implemented through references should remain valid according to defined constraints.
Key Acronyms
| Acronym | Meaning |
| ER | Entity Relationship |
| ERD | Entity Relationship Diagram |
| PK | Primary Key |
| FK | Foreign Key |
| MDM | Master Data Management |
| SQL | Structured Query Language |
See Entity Relationship Modeling in 4DAlert
Explore how 4DAlert implements the concepts in this guide as a working platform.