Parallel and Concurrent Operations in Relational Databases
George A. Thanos · 2003
Operations in the relational data model The relational model is one of the most used data model, it is a good choice for the implementation of databases. This is a powerful model, it supports simple and declarative languages, and it is value or iented. It has the ability to define operations on relations whose results are the mselves relations, and the operations can be combined and cascaded easily The first variant we can implement operations in the relational model is to allow any program to be an operation on relations. The main disadvantage of this case is that the programs have to know everything about the physical structures of data used, and the code depends on the particular structure selected at the design time. As a result it is preferred in database system to design query languages, that deals only with data model, not of a particular physical implementation of the model1,6,7. Supplementary to choose of a query language that operates only on relations, it is important that operations to have implementations that are efficient, since we want fast response to query on large databases.