Entity Framework Terminology

This topic defines terms frequently referenced in Entity Framework documentation. Links are provided to relevant topics where additional information is available.

Term	Definition
alias	An attribute of the Schema element in CSDL and SSDL schemas that can be substituted for the full namespace to shorten element references in the schema.
association	The definition of a relationship between entity types. For more information, see Association (EDM).
association set	A logical container for instances of associations of the same type. For more information, see Association Sets (EDM).
base type	A type in the Entity Data Model from which one or more derived types inherit some of their properties. For more information, see Inheritance (EDM).
command tree	A common, programmatic representation of all Entity Framework queries composed of one or more expressions. For more information, see Entity Framework Features.
complex type	A .NET Framework class that represents a complex property as defined in the conceptual model. Complex types enable scalar properties to be organized within entities. Complex objects are instances of complex types. For more information, see Complex Type Objects (Entity Framework).
ComplexType	The specification for a data type that represents a non-scalar property of an entity type that does not have a key property. For more information, see Complex Type (EDM).
conceptual model	An implementation of the Entity Data Model (EDM), specific to the Entity Framework, which represents an abstract specification for the data structures that define an entity-relationship representation of data in the domain of an application. For more information, see Data Modeling in the Entity Framework.
conceptual model file	An XML file that is a persisted representation of the conceptual model, expressed in CSDL. This file has a .csdl extension.
conceptual schema definition language (CSDL)	An XML-based language that is used to define a persisted format for the entity types, associations, entity containers, entity sets, and association sets of a conceptual model. For more information, see Conceptual Schema (CSDL).
constraint	Restricts the possible values of a property and makes sure that a value is valid. For more information, see Type Constraints (EDM).
container	A logical grouping of entity and association sets. For more information, see Entity Containers (EDM).
concurrency	A process that allows multiple users to access and change shared data at the same time. The Entity Framework implements an optimistic concurrency model. For more information, see Saving Changes and Managing Concurrency (Entity Framework).
data binding	The process or method for configuring controls on a form or Web page to fetch data from or write data to entity objects. For more information, see Binding Objects to Controls (Entity Framework).
deferred loading	When objects are returned by a query, related objects are not loaded at the same time. Instead they are loaded automatically when the navigation property is accessed. Also known as "lazy loading," deferred loading functionality is not explicitly provided by this version of the Entity Framework. For more information, see Load Related Objects (Entity Framework).
direction	Refers to the asymmetrical nature of some associations. Direction is specified with FromRole and ToRole attributes of a NavigationProperty or ReferentialConstraint element in a schema. For more information, see Entity Data Model Relationships and Association Element (SSDL).
eager loading	The process of loading a specific set of related objects along with the objects that were explicitly requested in the query. For more information, see Shaping Query Results (Entity Framework).
end	A participating entity in an association. For more information, see Role Attribute (Association CSDL) and Role Attribute (Association SSDL).
entity	A concept in the domain of an application from which a data type is defined. For more information, see Entities and Relationships (EDM).
EntityClient	System.Data.EntityClient is a storage-independent ADO.NET data provider that contains classes such as EntityConnection, EntityCommand, and EntityDataReader. Works with Entity SQL and connects to storage specific ADO.NET data providers, such as SqlClient. For more information, see EntityClient Provider for the Entity Framework.
entity container	Specifies entity sets and association sets that will be implemented in a specified namespace. For more information, see Entity Containers (EDM).
Entity Data Model (EDM)	A model that enables application data to be represented as a set of entities and relationships. For more information, see Data Modeling in the Entity Framework.
Entity Data Model Designer file	An XML file that encapsulates the conceptual model file, storage model file, and mapping file that form a persistent representation of a data model in the Entity Framework. This file also contains information that is used by the Entity Data Model Designer. This file has an .edmx extension. For more information, see ADO.NET Entity Data Model Designer Overview.
Entity Framework	A set of technologies that supports development of data-oriented software applications by enabling developers to work with conceptual models that are mapped to logical schemas in data sources. For more information, see Introducing the Entity Framework.
entity set	A logical container for entities of a given type and its subtypes. Entity sets are mapped to tables in a database. For more information, see Entity Sets (EDM).
Entity SQL	A storage-independent dialect of SQL that works directly with conceptual entity schemas and that supports Entity Data Model features such as inheritance and relationships. For more information, see Entity SQL Language.
entity type	A .NET Framework class that represents an entity as defined in the conceptual model. Entity types may have scalar, complex, and navigation properties. Objects are instances of entity types. For more information, see Object Services Overview (Entity Framework).
EntityType	The specification for a data type that includes a key and a named set of properties and represents a top-level item in a conceptual model or storage model. For more information, see Entity Type (EDM).
explicit loading	When objects are returned by a query, related objects are not loaded at the same time. By default, they are not loaded until explicitly requested using the Load method on a navigation property. For more information, see Load Related Objects (Entity Framework).
key	The attribute of an entity type that specifies which property or set of properties is used to identify unique instances of the entity type. Represented in the object layer by the EntityKey class. For more information, see Key Attribute (EntityType CSDL) and Key Attribute (EntityType SSDL).
LINQ to Entities	A query syntax that defines a set of query operators that allow traversal, filter, and projection operations to be expressed in a direct, declarative way in Visual C# and Visual Basic. For more information, see LINQ to Entities.
mapping	A specification of the correspondences between items in a conceptual model and items in a storage model. For more information, see Mapping Specification (MSL).
mapping file	An XML file that is a persisted representation of the mapping between the conceptual model and the storage model, expressed in MSL. This file has a .msl extension.
mapping specification language (MSL)	An XML-based language that is a persisted format for the mapping between items that are defined in a conceptual model and items that are defined in a storage model. For more information, see Mapping Specification (MSL).
metadata type hierarchy	A set of classes that enable you to interact with ADO.NET metadata. This type hierarchy provides programmatic support to represent a data model in the Entity Framework. For more information, see Metadata Type Hierarchy Overview.
metadata workspace	A class that represents the metadata runtime service component that provides support for retrieving metadata that is the runtime representation of a data model in the Entity Framework. For more information, see Metadata Workspace.
modification functions	Stored procedures that are used to insert, update, and delete data that is in the data source. These functions are used in place of Entity Framework generated commands. Modification functions are defined by the Function element in the storage model. The ModificationFunctionMapping element maps these modification functions to insert, update, and delete operations against entities that are defined in the conceptual model. For more information, see Stored Procedure Support (Entity Framework).
multiplicity	The number of entities that can exist on each side of a relationship, as defined by an association. Also known as cardinality. For more information, see Entity Data Model Relationships.
multiple entity sets per type	The ability for an entity type to be defined in more than one entity set. For more information, see Entity Sets (EDM).
navigation property	A property of an entity type that represents a relationship to another entity type, as defined by an association. Navigation properties are used to return related objects as an EntityCollection or an EntityReference, depending on the multiplicity at the other end of the association. For more information, see Navigation Properties (EDM).
query path	A string representation of a path that specifies which related objects to return when an object query is executed. A query path is defined by calling the Include method on an ObjectQuery. For more information, see Shaping Query Results (Entity Framework).
object context	Represents the entity container defined in the conceptual model. It contains a connection to the underlying data source and provides services such as change tracking and identity resolution. An object context is represented by an instance of the ObjectContext class. For more information, see Object Services Overview (Entity Framework).
object query	A query executed against a data model within an object context that returns data as objects. For more information, see Object Queries (Entity Framework).
object-relational mapping	A technique for transforming data from a relational database into data types that can be used in object-oriented software applications. Object Services provides such object-relational behavior by exposing entities in the conceptual model as entity types in an Entity Framework application. For more information, see Object Services Overview (Entity Framework).
Object Services	Services provided by the Entity Framework that enable application code to operate on entities like .NET Framework objects. For more information, see Object Services Overview (Entity Framework).
referential constraint	A constraint that is defined in the conceptual or storage model that indicates that an entity has a dependent relationship to another entity. This constraint means that an instance of a dependent entity cannot exist without a corresponding instance of the principle entity For more information, see Referential Constraints (Entity Framework).
relationship	A logical connection between entities. For more information, see Entity Data Model Relationships.
role	The name given to each End of an association to clarify the semantics of the relationship. For more information, see Role Attribute (Association CSDL) and Role Attribute (Association SSDL).
scalar property	A property of an entity that maps to a single field in the storage model.
simple type	A primitive type that is used for defining properties in the conceptual model. For more information, see Simple Types (EDM).
split entity	An entity type that is mapped to two separate types in the storage model. For more information, see How to: Define a Model with Single Entity Mapped to Two Tables.
storage model	A definition for the logical model of data in a supported data source, such as a relational database. For more information, see Data Modeling in the Entity Framework.
storage model file	An XML file that is a persisted representation of the storage model, expressed in SSDL. This file has a .ssdl extension.
store schema definition language (SSDL)	An XML-based language that is used to define a persisted format for the entity types, associations, entity containers, entity sets, and association sets of a storage model that frequently corresponds to a database schema. For more information, see Storage Metadata Schema (SSDL).
table-per-hierarchy	A method of modeling a type hierarchy in a database that includes the attributes of all the types in the hierarchy in one table. For more information, see How to: Define a Model with Table-per-Hierarchy Inheritance (Entity Framework).
table-per-type	A method of modeling a type hierarchy in a database that uses multiple tables with one-to-one relationships to model the various types. For more information, see How to: Define a Model with Table-per-Type Inheritance (Entity Framework).

See Also

Concepts

ADO.NET Entity Framework
Introducing the Entity Framework
Entity Framework Resources

Other Resources

Getting Started (Entity Framework)
Application Scenarios (Entity Framework)