Search results
Results from the WOW.Com Content Network
Today, even where ER modeling could be useful, it is uncommon because many use tools that support similar kinds of model, notably class diagrams for OO programming and data models for relational database management systems. Some of these tools can generate code from diagrams and reverse-engineer diagrams from code.
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.
It was developed by IBM for IMS (information Management System), and is a set of organized data in tree structure. DB record is a tree consisting of many groups called segments. It uses one-to-many relationships, and the data access is also predictable. Network model; Relational model; Entity–relationship model. Enhanced entity–relationship ...
A physical data model (or database design) is a representation of a data design as implemented, or intended to be implemented, in a database management system. In the lifecycle of a project it typically derives from a logical data model , though it may be reverse-engineered from a given database implementation.
The designer determines what data must be stored and how the data elements interrelate. With this information, they can begin to fit the data to the database model. [1] A database management system manages the data accordingly. Database design is a process that consists of several steps.
The database design documented in these schemas is converted through a Data Definition Language, which can then be used to generate a database. A fully attributed data model contains detailed attributes (descriptions) for every entity within it. The term "database design" can describe many different parts of the design of an overall database ...
For example, think of A as Authors, and B as Books. An Author can write several Books, and a Book can be written by several Authors. In a relational database management system, such relationships are usually implemented by means of an associative table (also known as join table, junction table or cross-reference table), say, AB with two one-to-many relationships A → AB and B → AB.
Edgar Frank "Ted" Codd (19 August 1923 – 18 April 2003) was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases and relational database management systems.