Network And Hierarchical Databases Systems Computer Science Essay

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William Hill is one of a largest bookmaking company in the UK leisure industry. In the UK market share William Hills only second to the Coral Racing Company. It has over 2500 retail outlets in the United Kingdom and another 300 outlets elsewhere in the world. It was born in 1934. In that time betting wasn't even legal, so they started the business behind the doors and it was known as being knowledgeable, honest and trust worthy. In 1966 with gambling become legal William Hill has joined in to the market opening up retail outlets in most popular cities in throughout UK. With the arrival of television, betting became more of a leisure activity. In 1998 William Hill has became the first in the business to introduce an online betting capability to their portfolio. According to their CEO some things hasn't change though that's their reputation for honesty and integrity and exceptional customer service are much more important to compete in the business.

There are five major competitors in the UK leisure industry. Which are William Hill, Ladbrokes, Tote, Coral and Betfred, together they achieved of just over 80% of all betting shops in the high street. Out of all William Hill has the biggest share of 25% in the total number of betting outlets. Online gambling has contain large number of competitors among them according to marketing research done by the William Hill itself in 2008, some 24% of regular online bettors had a William Hill betting accounts. The web has changed the expression of the industry, " not only giving companies access to new customers has different interest"( www.williamhillplc.co.uk ), but also enabling a far more exciting portfolio of gaming and betting products are offered. Gambling is a leisure pastime in certain age group of people, majority is elderly as they enjoyed this as nothing else. It is mostly popular in the UK, where betting on sporting events, horse racing in particularly, have long been part of British culture.

Throughout this assignment I'll explain the three types of Database Management Systems in detail and I'm trying to investigate why William Hill use ORDBMS type database instead of any other type of databases and what are the characteristics of each type of database also advantages and disadvantages of each type of database. In the final part of this assignment I would like to prove why William Hill using ORDBMS and my recommendations which I study through this assignment.

RDBMS

The insufficient capabilities of network and hierarchical databases systems resulted in the creation of the relational database management system. In the other words relational data model is the develop version of the network database with some additional features. Relational model, just like hierarchical and network models are based upon tables and use parent/child relationships. A table is a basic building unit of the relational database. A table consists of rows and columns. Each table has a unique name in the database. The good relational design would make sure that such a record describes an entity. The record should not contain irrelevant information. For an example customer table deals with the customer information only, its records should not contain information about for instance, products that this customer ordered from the company. There is no theoretical limit on the number of rows a table could have in RDBMS, however some implementations enforce restrictions. Furthermore there are practical considerations to the limits like data retrieval speed, amount of storage in database depends on the database hardware itself. Tables in RDBMS might or might not be related to the other tables. As I mentioned before, RDBMS is built upon parent/child relationship notion, but unlike in hierarchical, network databases these relations are based only on the values in the table columns. Also these relationships are meaningful in logical scenarios and RDBMS may need to run a directory service along side to the database software to get the maximum productivity.

Characteristics of RDBMS

1. The relational character of the RDBMS makes it appropriate for processing complicated, sophisticated data models that require many tables, foreign key values and joining operations, which make the RDBMS complex to handle.

2. The RDBMS character has many mechanism designed to guarantee data integrity. This includes rollback operations and referential integrity.

3. The RDBMS is designed to handle repeatedly altering data. on the other hand, RDBMS can also store enormous amounts of historical data, which can be later retrieve when required.

4. Transactions operate on a consistent view of the data record. When the transaction is finished, it'll rollback to consistent state again.

5. Transactions run isolated from other connections. So if connections are running simultaneously, the effects of transaction A is not visible to transaction B, and vice-versa, until the transaction is completed.

6. Once the transaction begging, till it's finished the activities occurs in between are not durable or persistent for a example if crashes rollback feature will come to alive and forced to go back to previous consistent state.

7. Roll back feature is much more capable of reversing even the tiny changers to its tables, row or column involved in simple transaction.

8. A query is a data retrieval utility allows data manipulation and tables in RDBMS.

9. RDBMS are regularly used application oriented programmes to written data transaction.

10. RDBMS contains unique operation system to supports each application individually.

Advantages of RDBMS

1. RDBMS are that the system is simple, flexible, and productive. Because the tables are simple, data is easier to understand and communicate with others. RDBMS are flexible because users do not have to use predefined keys to input information.

2. Ad hoc query capabilities (SQL) in RDBMS are more productive because SQL is easier to learn. This allows users to spend more time inputting instead of learning.

3. it's ease handle, users can create and access data and extend it if needed. After the original database is created, new data categories can be added without the existing application being changed.

4. Improved conceptual simplicity and easier database design, implementation, management and usage.

Disadvantages of RDBMS

1. Transaction processing is generally short lived. Concurrency control primitive and protocols are not particularly suited for long duration transactions.

2. Entity creation of relations does not match to entities in real world. Division of a real world entity into many relations, with a physical representation that reflect the structure, is insufficient leading to many joins during query processing.

3. RDBMS has only one construct for representing data and relationship between the entities. There is no mechanism to distinguish between entities and relationships. It's said that the relational model is semantically overloaded.

4. Integrity is usually expressed in terms of constraint. Which are consistency rules that not permitted to violate. But RDBMS does not fully support to this constraint. This leads to database inconsistency.

5. Relational models assumes both horizontally and vertical homogeneity. This fixed structure is too restrictive for many real world objects that have complex structure and its leads to unreal joints which are inefficient.

ORDBMS

Modern database applications need to store and control objects that are neither small nor simple, and to perform operations on these multimedia objects that are not predefined. So ORDBMS was created to handle those new types of data multimedia type data such as audio, video, and image files that RDBMS were not capable of holding. On the other hand its development was the result of improved usage of object-oriented programming languages, DBMS software fills the huge difference between these two concepts.

Characteristics of ORDBMS

1. ORDBMS are often considered the bridge between RDBMS and OODBMS, implementing the ease of use of the RDBMS and the flexibility of the OODBMS to handle complex data types.

2. RDBMS employ a data model that attempts to incorporate OO features into RDBMS.

3. The main contribution of the ORDBMS is its ability to handle complex, object-centric, constant data while maintaining the easy-to-use RDBMS querying methods to operate on that data.

4. An ORDBMS is employed in application domains where complex data types are required and simply cannot be managed using a traditional RDBMS and its accompanying query language.

5. The friendly feature in an ORDBMS allows companies to carry on using their current system, without having to do any key changes.

6. Its gives an opportunity to companies and programmers to use parallel to the object oriented systems.

7. Its process the hieratical connective data in a view of that the attribute inheritance. So ORDBMS has greater speed of processing data.

Advantages of ORDBMS

1. As I mentioned in ORDBMS characteristics this has a feature that allows companies to carry on using their current system, without having to do any key changes.

2. Can use parallel to the object oriented concept.

3. An ORDBMS arranged the data and behaviour of business objects within an abstract data model.

4. Object Relational query capability contract with the real objects like, personal name, part, code, polygon and video, instead of integer values.

Disadvantages of ORDBMS

1. Complex than the RDBMS.

2. Implementing ORDBMS is much more expensive than implementing relational database management system in an organisation.

3. Unclear if the ORDBMS will actually combine relationships and encapsulated objects to correctly and completely mirror to the real world objects.

4. Provision of languages, which will front end to SQL and will provide a migration path for existing SQL users.

OODBMS

"OODBMS is a database management system (DBMS) that supports the modelling and creation of data as objects. This includes some kind of support for classes of objects and the inheritance of class properties and methods by subclasses and their objects." ( www.odbms.org) OODBMS are DBMS which are based on an Object Oriented Data Model. This data models are often inspired by OO programming languages, such as C++. OODBMS are capable of storing complex objects, objects that are contain of other objects, and multivalve attributes. The great advantage of OODBMS is that it is not necessary to transform the UML classes into a logical schema unlike RDBMS. OODBMS operate on complex information efficiently because elements of information are "pre-joined" together and stored as a whole in the database. That's a major deference to RDBMS where elements of data are stored in their simplest or normal forms in tables. To uncover relationships among data in a relational database, these tables must be joined together however to uncover relationships in an OODBMS, objects forming the relationships are simply fetched. OODBMS are typically based on a data shipping approach. Data items are shipped from servers to clients so that query processing and application processing can be performed at the database. But the data shipping approach does not dictate where in the system the mapping between objects and pages resides. Data-shipping moves the data closer to the applications, allowing to reduced the time to interaction between the application and the DBMS. OODBMS express their requests logically, in terms of objects. The objects themselves, however, are stored on disk in units of pages. Therefore, an OODBMS must manage storage in terms of data pages.

Characteristics of OODBMS

The system must maintain multifaceted objects. Complex objects are built from simpler ones by applying constructors to them. Supporting complex objects also needs that suitable operators must be provided for dealing with such objects. Operations on a complex object must spread equivalent to all its components.

2. Multiple users can access the database at same time simultaneously without creating inconsistence result due to the interaction of concurrent operation.

3. Users can create data items which reside in persistent storage, rather than volatile memory without creating files which contain the data and are referenced by their names.

4. Similar entity instances are classified into types or classes. Type defines as properties and operations which are available to direct its instances.

5. The relationship between entity types and instances are known to the system and can be utilized to formulate queries which span the data.

6. Objects can be assemblies of other object or objects are not limited to primitive domains. In the other words can call it as composition.

7. The set of operations, structure and constrain available to applications is not limited and fixed. Applications define new operations and structure which are used the same way as the build in structure and operations.

Advantages of OODMS

Object-oriented database concept is a more natural way of view and it's reusable, stable and reliable. The pre-defined activities on the system does not depends on type of application running on the system when it's occurs.

2. Object oriented databases can be extensive to hold complex data such as audio video, images, digital along with other multimedia operations.

3. OODBMS is that interactions are represented in openly, it's tend to provide both navigational and associative access to information.

4. Users are pretty much independent they can invoke their own system or methods of access to data in the database or how it should be represented or manipulated to the others.

5. This has extended databases into an unknown to RDBMS vision. Medicine, multimedia and energy physics are the new industries totally relying on OODBMS.

Disadvantages in OODBMS

1. Their technology is immature and they are only used in niche applications, such as CAD & CAM.

2. AD-hoc querying compromise the encapsulation.

3. Locking the object level performance.

4. OODBMS are much more complicated than the other two types of database management systems.

5. Lack of support for the views and insufficient security features.

Recommendation

Having identifying what are the main requirements in the William Hill database system,

ORDBMS is the most suitable database management system out of all the others. Most

importantly compare to the other management system ORDBMS is the easiest to

implement and the most cost effective. If they want, William Hill can choose OODBMS

instead, but that will need a large sum of money to implement and maintain it

unnecessarily. Also database administrators want be able to use queries in OODBMS.

ORDBMS and ODBMS design to deal with much more complex, access, search and

manipulate data types and objects. William Hill database purely deal with simple standard

data models and simple snap shots ( copies of placed bets ) example: previous result in text format, customer record including his stakes and winning, placed bets, details about players, images of placed bets, sports and future competitions ect..... As I explained in above ORDBMS is the extended version of RDBMS. The friendly feature in an ORDBMS allows companies to carry on using their current system, without having to do any key changes. Also Its gives an opportunity to companies to use parallel to the object oriented systems. Having such a database management system is ideal for the William Hill to carry out their day to day business.

Conclusion

Modern database applications need to store and control large objects or complex data model and to perform operations on these multimedia objects that are not predefined. So ORDBM was created to handle those ORDBMS was created to handle multimedia data such as audio, video, and image files that RDBMS were not equipped to handle. Fast, reliable and scalable data storage services are critical for a wide range of applications today. The great merge of the two concepts, relational and object oriented programming database management systems provides the basis for object relational databases system. Having great storage capacity, access speed and management commands of object databases, makes ORDBMS more productive to overcome the database market. Easy connectivity using bridges with main database vendors and its features will make it the market leader in near future.

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