Data model Guide, Meaning , Facts, Information and Description
A data model is a model that describes in an abstract way how data is represented in an information system or a database management system.This term is ambiguously defined to mean:
- how data generally is organized, e.g. as described in Database management system. This is sometimes also called "database model"
- or how data of a specific application is organized logically (e.g. the data model of some business)
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2 Organization of Data in a Specific Application (Domain) 3 Tools for Creating a Data model for an Application |
General Organization of Data
In general the first aspect ("database model") describes the following:
For example in the relational model all data is represented by
mathematical relations (or, to be precise, a slightly generalized version thereof).
There exists a general language for specifying constraints (first-order logic), and for manipulations and querying the data the relational algebra, tuple calculus and domain calculus are introduced.
Additional information about this topic can also be found in database management system.
For a specific application tables (objects, relations, ..., the naming conventions depend on the general model) are defined, for example "customer", "order", "item" as well as relations between them ("customer orders items").
If a relational model is used, sets of specific constraints (candidate keys, foreign keys) have to be defined (using the appropriate language as defined for the general model, e.g. SQL).
While simple data models consisting of few tables or objects can be created "manually" large applications need a more systematic approach. The Entity-Relationship Model method is used to establish a domain specific data model. Other methods like the Functional Data Model and the Object Role Model also describe subsets/aspects of a data model and the application based on it. The Unified Modeling Language (UML) is another method more related to object-oriented data models. Especially the "Object Model" part has a number of parallel representations with the Entity-Relationship Model. This is an Article on Data model. Page Contains Information, Facts Details or Explanation Guide About Data model Organization of Data in a Specific Application (Domain)
Tools for Creating a Data model for an Application