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An entity–relationship model (or ER model) describes interrelated things of interest in a specific domain of knowledge. A basic ER model is composed of entity types (which classify the things of interest) and specifies relationships that can exist between entities (instances of those entity types).
An entity–relationship model (ERM) is an abstract conceptual representation of structured data. Entity–relationship modeling is a relational schema database modeling method, used in software engineering to produce a type of conceptual data model (or semantic data model ) of a system, often a relational database , and its requirements in a ...
The enhanced entity–relationship (EER) model (or extended entity–relationship model) in computer science is a high-level or conceptual data model incorporating extensions to the original entity–relationship (ER) model, used in the design of databases.
The most popular example of a database model is the relational model (or the SQL approximation of relational), which uses a table-based format. Common logical data models for databases include: Navigational databases. Hierarchical database model; Network model; Graph database; Relational model; Entity–relationship model. Enhanced entity ...
Snowflake schema used by example query. The example schema shown to the right is a snowflaked version of the star schema example provided in the star schema article. The following example query is the snowflake schema equivalent of the star schema example code which returns the total number of television units sold by brand and by country for 1997.
In addition, a description of the database technology to be employed must be generated, as well as a description of the processes that are to manipulate the data. It is also important to design interfaces to the data by other systems, as well as a design for the infrastructure that is to support common data operations (i.e. emergency procedures ...
Example of an IDEF1X diagram. Integration DEFinition for information modeling (IDEF1X) is a data modeling language for the development of semantic data models.IDEF1X is used to produce a graphical information model which represents the structure and semantics of information within an environment or system.
Data flow diagram with data storage, data flows, function and interface A data-flow diagram is a way of representing a flow of data through a process or a system (usually an information system ). The DFD also provides information about the outputs and inputs of each entity and the process itself.