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The terms schema matching and mapping are often used interchangeably for a database process. For this article, we differentiate the two as follows: schema matching is the process of identifying that two objects are semantically related (scope of this article) while mapping refers to the transformations between the objects. For example, in the ...
The database schema is the structure of a database described in a formal language supported typically by a relational database management system (RDBMS). The term " schema " refers to the organization of data as a blueprint of how the database is constructed (divided into database tables in the case of relational databases ).
Conceptual schema: describes the semantics of a domain (the scope of the model). For example, it may be a model of the interest area of an organization or of an industry. This consists of entity classes, representing kinds of things of significance in the domain, and relationships assertions about associations between pairs of entity classes.
The Data Base Task Group (DBTG) was a working group founded in 1965 by the Cobol Committee, formerly Programming Language Committee, of the Conference on Data Systems Language . It was initially named the List Processing Task Force and later renamed to DBTG in 1967.
Even an extreme database-centric architecture called RDBMS-only architecture [6] [7] has been proposed, in which the three classic layers of an application are kept within the RDBMS. This architecture heavily uses the DBPL (Database Programming Language) of the RDBMS. An example of software with this architecture is Oracle Application Express ...
The five level schema architecture includes the following: Local Schema is basically the conceptual model of a component database expressed in a native data model. [3] Component schema is the subset of the local schema that the owner organisation is willing to share with other users of the FDBS and it is translated into a common data model. [3]
A database contains tables. Relationships between them are modelled as other tables. [8] A key feature of Mnesia's high-availability approach is that tables can be reconfigured within a schema and relocated between nodes, not only while the database is still running, but even while write operations are still going on.
The logical schema was the way data were represented to conform to the constraints of a particular approach to database management. At that time the choices were hierarchical and network. Describing the logical schema, however, still did not describe how physically data would be stored on disk drives. That is the domain of the physical schema.