The Limitations Of RDBMS Systems

The Limitations Of RDBMS SystemsTo combat the demarcation lines of RDBMS and meet the ch in allenge of the increasing rise of the earnings and the Web, computer programmemers developed determination- orient informationbases in the 1980s. The main objective of Object-Oriented informationbase Management Systems, comm nevertheless now cognize as OODBMS, is to provide consistent, entropy independent, secure, controlled and extensible selective information heed function to support the object-oriented model. They were created to handle big and interlacing data that relational databases could not. there be important characteristics involved with object-oriented databases. The most important characteristic is the connexion of object-oriented programming with database technology, which provides an integrated application development outline. Object-oriented programming results in 4 main characteristics inheritances, data encapsulation, object identity, and polymorphism.Inherita nce allows wholeness to develop solutions to interlacing conundrums incrementally by defining new objects in terms of previously outlined objects. data encapsulation or simply encapsulation allows the hiding of the internal state of the objects. Encapsulated objects ar those objects that whoremonger only be assessed by their regularitys instead of their internal states. thither be three types of encapsulated objects users and developers should recognize. The first is full encapsulation, in which all the operations on objects are make through message sending and method execution. The second is write encapsulation, which is where the internal state of the object is visible only for reading operations. The third is partial encapsulation, which involves allowing direct access for reading and indite for only a part of the internal state.Object identity allows objects of the database to be independent of each different.Polymorphism and fighting(a) binding allow one to define op erations for one object and then to share the spec of the operation with other objects. This allows users and/or programmers to compose objects to provide solutions without having to write work out that is specific to each object.The speech communication important to OODBMS is data definition and handling language (DDML). The use of this language allows persistent data to be created, updated, deleted, or retrieved. An OODBMS necessarily a computational versus a relational language because it can be employ to avoid impedance mismatch. DDML allows users to define a database, including creating, altering, and drop control panels and establishing constraints. DDMLs are used to maintain and research a database, including updating, inserting, modifying, and querying data.The OODBMS has many advantages and advantages. First, object-oriented is a more natural way of thinking. Second, the defined operations of these types of systems are not dependent on the particular database appl ication running at a given moment. Third, the data types of object-oriented databases can be all-embracing to support decomposable data such as images, digital and audio/video, along with other multi-media operations. Different benefits of OODBMS are its reusability, stability, and reliability. Another benefit of OODBMS is that relationships are represented explicitly, often supporting both navigational and associative access to information. This translates to improvement in data access performance versus the relational model.Another important benefit is that users are allowed to define their own methods of access to data and how it will be represented or manipulated. The most significant benefit of the OODBMS is that these databases have extended into areas not known by the RDBMS. Medicine, multimedia, and high-energy physics are just a few of the new industries relying on object-oriented databases.As with the relational database method, object-oriented databases similarly have disadvantages or limitations. One disadvantage of OODBMS is that it lacks a common data model. There is also no current standard, since it is legato considered to be in the development stages.Who is currently using an OODBMS to handle mission critical data?The following information was gleaned from the ODBMS Facts website.The Chicago Stock Exchange manages stock trades via a Versant ODBMS.Radio Computing Services is the worlds largest radio software company. Its product, Selector, automates the needs of the entire radio station from the music library, to the newsroom, to the sales department. RCS uses the POET ODBMS because it enabled RCS to integrate and form various elements, regardless of data types, in a single program environment.The Objectivity/DB ODBMS is used as a data alluviation for system component naming, satellite mission planning data, and orbital management data deployed by Motorola in The Iridium System.The Object Store ODBMS is used in Southwest Airlines Home Ga te to provide self servicing to travellers through the Internet.Ajou University Medical Center in South Korea uses Intersystems Cach ODBMS to support all hospital functions including mission-critical departments such as pathology, laboratory, blood bank, pharmacy, and X-ray.The Large Hadron Collider at CERN in Switzerland uses an Objectivity DB. The database is currently being tested in the hundreds of terabytes at data rates up to 35 MB/second.As of November, 2000, the Stanford Linear gas Center (SLAC) stored 169 terabytes of production data using Objectivity/DB. The production data is distributed across several hundred processing nodes and over 30 on-line(a) servers.Below is a list of advantages and disadvantages of using an OODBMS over an RDBMS with an object oriented programming language.AdvantagesComposite Objects and kinships Objects in an OODBMS can store an arbitrary add of atomic types as well as other objects. It is thus feasible to have a large variety which holds many medium coat classes which themselves hold many smaller classes, ad infinitum. In a relational database this has to be do either by having one huge table with lots of null fields or via a number of smaller, normalized tables which are linked via foreign keys. Having lots of smaller tables is still a problem since a join has to be performed every time one wants to query data based on the Has-a relationship amidst the entities. Also an object is a better model of the real world entity than the relational tuples (attributes) with regards to complex objects. The fact that an OODBMS is better suited to handling complex, interrelated data than an RDBMS agency that an OODBMS can outperform an RDBMS by ten to a thousand multiplication depending on the complexity of the data being handled.Class Hierarchy Data in the real world is usually having hierarchical characteristics. The ever customary Employee example used in most RDBMS texts is easier to describe in an OODBMS than in an RD BMS. An Employee can be a Manager or not, this is usually done in an RDBMS by having a type identifier field or creating another(prenominal) table which uses foreign keys to indicate the relationship between Managers and Employees. In an OODBMS, the Employee class is simply a parent class of the Manager class.Circumventing the Need for a Query Language A query language is not essential for accessing data from an OODBMS unlike an RDBMS since interaction with the database is done by transparently accessing objects. It is still possible to use queries in an OODBMS however.No Impedence Mismatch In a typical application that uses an object oriented programming language and an RDBMS, a signifcant amount of time is usually spent mapping tables to objects and back. There are also various problems that can occur when the atomic types in the database do not map cleanly to the atomic types in the programming language and vice versa. This impedance mismatch is completely avoided when using an O ODBMS.No primitive Keys The user of an RDBMS has to worry about uniquely identifying tuples by their values and reservation sure that no two tuples have the same primary key values to avoid error conditions. In an OODBMS, the unique identification of objects is done behind the scenes via OIDs and is completely invisible to the user. Thus there is no limitation on the values that can be stored in an object.One Data Model A data model typically should model entities and their relationships, constraints and operations that change the states of the data in the system. With an RDBMS it is not possible to model the dynamic operations or rules that change the state of the data in the system because this is beyond the scope of the database. Thus applications that use RDBMS systems usually have an Entity Relationship diagram to model the static parts of the system and a scatter model for the operations and behaviours of entities in the application. With an OODBMS there is no disconnect be tween the database model and the application model because the entities are just other objects in the system. An entire application can thus be comprehensively modelled in one UML diagram.