Object RDBMS

PostgreSQL is generally referred to as an Object Relational Database Management System (ORDBMS). The use of the word object implies objects in the sense of an object-oriented computer language. While not intended to be fully object-oriented in the same sense as a computer language, an ORDBMS shares the essential aspects of objects. These include composite data types, methods (functions), and inheritance. 

This chapter has shown how composite data types can be of great use in chemical databases. The components of a composite data type are either basic SQL data types, or other composite data types. This is the same way an object is defined in an object-oriented computer language. This level of abstraction can help simplify the development of complex databases. 

Another important aspect of objects is the methods that operate on them. An ORDBMS calls these functions, but the effect is the same. As shown in this chapter, the functions defined for new data types enable them to be integrated in the SQL language and handled just like standard SQL data types. This can be by casting the data type, for example, to allow range data to be treated as float. New functions that operate exclusively on range data can be defined, such as range cmp. The ability to define operators of new data types enhances their usability and integration into SQL even more. 

An ORDBMS is a kind of hybrid of a traditional RDBMS and a fully object-oriented OODBMS. The range of types of DBMS and their advantages and disadvantages is discussed elsewhere.8-10 

Plpgsql. 2008. http //www.postgresql.Org/docs/8.2/static/plpgsql.html (accessed April 18, 2008). 

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For a variety of appHcations such as computer-aided engineering systems, software development, or hypermedia, the relational database model is insufficient. In an RDBMS, it is difficult to model complex objects and environments the various extensive tables become complicated, the integrity is problematic to observe, and the performance of the system is reduced. This led to two sophisticated object-based models, the object-oriented and the object-relational model, which are mentioned only briefly here. For further details see Refs. [10] and [11]. 

The main difference from the relational DBS is that the data are now stored in object types with a unique identity number (ID), attributes, and operations. Therefore, the relationship between objects is completely different from that in an RDBMS. 

Unlike the procedural languages discussed above, C language functions are compiled separately. The code itself is not included in the SQL create function command. Instead, the create function command refers to a compiled object such as shared object (.so) file located in some directory on the server running the RDBMS. For example, the CHORD oe smiles function is defined as follows. 

A prototype system framework of PEEE has been developed using Java and Visual Basic as object-oriented programming languages, while SQE server and MS-Access are used as RDBMS for data repository for the plant model elements. Such prototype solution will enable all plant users to utilize a standard user interface to manipulate plant lifecycle data/information/knowledge. The prototype system can be used as the framework to develop CAPE-SAFE as well as other components within PEEE. 

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