Learning Team A Week 6- Learning Team Reflexion
Jose Banks, Kirk Williams, Cadence Scott, Frank Carr, Marika Hughey, Elmehdi Ibnamar
DBM/502 Database Management
June 25th, 2012
Liz Musil

In the late 1960s and early 1970s, there were two mainstream approaches to constructing database Management System’s (DBMS’s). The first approach was based on the hierarchical data model typified by IMS (information Management System). The second approach was based on the network data model, which its main aim of creation was to create a standard database that would unify number of functionalities such as programming languages (queries) for data retrieval, and the inability of the existing database to represent complex relationships database management systems
(DBMS). However, these two models had some fundamental disadvantages:
• Complex programs had to be written to answer even simple queries
• There was minimal data independence
• There was no widely accepted theoretical foundation. In reference to DBMS and the ability of building complex relational system, many Relational database management system RDBMS has been developed (also referred as a second generation of
DBMSs). RDBMS was used extensively in the 80’s and 90’s, however due to its limitation to respond the more complex entity and, needs of companies and the increasing complexity of database applications. Two “new” data models have emerged; the Object-Relational Database Management
Systems (ORDBMS) and Object-Oriented Database Management Systems (OODBMS), which subscribes to the relational and object data models respectively. The OODBMS and ORDBMS have been combined to represent the third generation of Database Management Systems.
Current trends of database model: 1. Distributed databases: Distributed databases are the most common databases utilized over the companies and in professional environments. Distributed database means that Parts of the database are stored physically in one location, and other parts are stored and maintained in other locations. There are two main ways of distributing a database. The central database can be partitioned so that each remote processor has the necessary data to serve its local area. Changes in local files can be

justified with the central database on a batch basis, often at night.
Another strategy is to replicate the central database at all remote locations. This strategy also requires updating of the central database off hours. advantage and drawbacks of distributed processing and distributed databases Distributed systems reduce the vulnerability of a single, massive central site. They permit increases in systems’ power by purchasing smaller less expensive computers. Finally, they increase service and responsiveness to local users. Distributed systems, however, are dependent on high quality telecommunication lines, which themselves are vulnerable. Moreover, local databases can sometimes depart from central data standards and definitions, and they pose security problems by widely distributing access to sensitive data. The economies of distribution can be lost when remote sites buy more computing power than they need. Despite these drawbacks, distributed processing is growing rapidly.

2. Object Oriented and Hybrid Models Object oriented database management system (OODBMS) is a complex technology that necessitates a profound knowledge of the object, and class. The objective is to search and manipulate data about objects, which have complex inner data structures. A hybrid Models is a combination of OODBMS and RDBMS.
Traditional DBMS including RDBMS store only data without the procedure required to manipulate and retrieve data. However, the OODBMS store objects. An object contains data about an entity, and also the methods that process those data. An object may be anything to which a concept applies, e.g. a number, a document, a vector, a sound or an image.
The complexity of OODBMS resides in the facts that one object may have contain another object and that object may in his turn contain another object, and at the end we could have a tree of hierarchical objects. This enables the capture of highly complex data structures.
Unlike the relational data model, the object-oriented data model is not based on a formal

mathematical model, but is a collection of concepts such as data and behavior encapsulation, inheritance, reuse and message passing, which have proved to be of great use in developing applications. These and other concepts allow the OODBMS to capture more of the semantics of the real world. However, although OODBMS have significant strengths, they are not free of limitations, the foremost of which is the lack of a strong underlying theory. Further, for OODBMS there still exists the lack of a standardized easy-to-use query language.
Object oriented and hypermedia databases can store graphics and other types of data in addition to conventional text data to support multimedia applications. Hyper media databases allow data to be stored in nodes linked together in any pattern established by the user. Web sites use a hypermedia database approach to store information as interconnected pages containing text, sound, video and graphics. 3. Data warehouse Data warehouse is standardized and consolidated platform, so that it can be used across the enterprise for management analysis and decision-making. The data is available for anyone to access as needed but cannot be altered. A data warehouse system includes a range of ad hoc and standardized query tools, analytical tools, and graphical reporting facilities. These systems can perform high-level analysis of patterns or trends, but they can also drill into more details when needed. Database warehouses not only offer improved information, but also they make it easy for decision makers to obtain it. They even include the ability to model and remodel the data. These systems also enable decision makers to access data as often as they need without affecting the performance of the underlying operational systems. 4. Database cloud computing There are a number of advantages to using the Web to access an organization’s internal database. Web browser software is extremely easy to use, requiring much less training than even user-friendly database query tools. The web interface requires no changes to the legacy database.
Companies leverage their investments in older systems because it cost much less to add a Web

interface in front of a legacy system than to redesign and rebuild the system to improve user access. http://www.cpaireland.ie/UserFiles/File/students/Articles/DatabaseITarticle.pdf

Future database Models The desired evolution of DBMSs, therefore, could take the form of a Postrelational DBMS that decouples the storage mechanism from the access mechanism. One way to think of this is that there is an underlying DBMS that operates only in terms of very generic database concepts, analogous to an abstract class in object-oriented programming. A DBMS implementation could be derived from this base DBMS that applied the constraints and assumptions of a particular model to the data.
Additional DBMS implementations could also be placed on top of the base DBMS, all having native and natural access to the data. Another way to look at this is to think of a data model as a type of view - it is a user's perception of the data. The underlying storage mechanism does not need to necessarily conform to that view internally, but only to ensure that the view remains consistent for the consumers of that view. http://www.informationweek.com/news/development/database/229209559 References:
Database Resources, Subject: Information Technology for Managers, author’s name: Seamus Rispin, Retrieved from: http://www.cpaireland.ie/UserFiles/File/students/Articles/DatabaseITarticle.pdf

DBMS Past, Present, and Future, published date: October 01, 2008 12:00 AM, retrieved from: http://www.informationweek.com/news/development/database/229209559