Relational model - Essay Example

One of the technology terms that most people have become accustomed to hearing either at work or while surfing the Internet Is the database. The database used to be an extremely technical term, however with the rise of computer systems and information technology throughout our culture, the database has become a household term. A database is a structured collection of records or data that is stored in a computer system. In order for a database to be truly functional, it must not only store large amounts of records well, but be accessed easily. In addition, new Information and changes should also be fairly easy to Input.

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In order to have a highly efficient database system, a program that manages the queries and Information stored on the system must be incorporated. This is usually referred to as DB’S or a Database Management System. Besides these features, all databases that are created should be built with high data integrity and the ability to recover data if hardware fails. Types of Databases There are several common types of databases. Each type of database has its own data model (how the data Is structured). They Include Flat Model, Hierarchical Model, Relational Model, and Network Model. The Flat Model Database

A flat database is a simple database system in which each database is represented as a single table in which all of the records are stored as single rows of data, which are separated by De limiters such as tabs or commas. The table is usually stored and physically represented as a simple text file. Because of the limitations of flat databases, they are not unsuitable for most software applications In which there are a need to represent and store complex business relationships. However, some application developers still use flat files in order to reduce the cost and complexity of integrating a relational database. Like relational databases, flat databases cannot represent complex relationships between entities. They also have no way of enforcing constraints between data. For instance in an application used by a commercial bank, It Is a good Idea to ensure that, at the time of creation, a new account must be linked to an existing customer. In a relational database this is easily enforced using the concept of foreign keys to ensure that customer IDs are filled in while creating an account, and also that said customer IDs already exist in another table.

This is not possible with flat databases, which means hat such a constraint has to be enforced by other means, such a through application code logic. Another Limitation of flat databases vials-a-vials relational databases Is the formers lack of query and indexing capability. SQL queries cannot be written in flat databases because the data is not relational, and indexes cannot be created because the data is all lumped together in one table. Data in a flat database is typically only readable by and useful to the software application associated with the database. Ever grow large enough for the limitations outlined above to really become a problem. Some real-life examples of flat databases are contact lists in a mobile phone and the storage of a high-scores list in a simple video game. In such cases, there would be little point and no Justifiable expense in integrating a complex relational database engine into the computing platform because a simple flat database will do nicely. The Hierarchical Model Database The hierarchical model database resembles a tree like structure, such as how Microsoft Windows organizes folders and files.

In a hierarchical model database, each upward link is nested in order to keep data organized in a particular order on a same level list. A hierarchical database is a design that uses a one-to-many relationship for data elements. Hierarchical database models use a tree structure that links a number of disparate elements to one “owner,” or “parent,” primary record. The idea behind hierarchical database models is useful for a certain type of data storage, but it is not extremely versatile. Its limitations mean that it is confined to some very specific uses.

For example, where each individual person in a company may report to a given department, the department can be used as a parent record and the individual employees will represent secondary records, each of which links jack to that one parent record in a hierarchical structure. Hierarchical databases were popular in early database design, in the era of mainframe computers. While some IBM and Microsoft models are still in use, many other types of business databases use more flexible models to accommodate more sophisticated types of data management.

Hierarchical models make the most sense where the primary focus of information gathering is on a concrete hierarchy such as a list of business departments, assets or people that will all be associated with specific higher-level primary data elements. The Network Model In a network model, the defining feature is that a record is stored with a link to other records – in effect networked. These networks (or sometimes referred to as pointers) can be any type of information such as node numbers or even a disk address. A network database model is a database model that allows multiple records to be linked to the same owner file.

The model can be seen as an upside down tree where the branches are the member information linked to the owner, which is the bottom of the tree. The multiple linkages which this information allows the network database model to be very flexible. In addition, the relationship that the information has in the network database model is defined as many-to-many relationship because one owner file can be linked to many member files and vice versa. The network database model was invented by Charles Bushman in 1969 as an enhancement of the already existing database model, the hierarchical database model.

Because the hierarchical database model was highly flaw, Bushman decided to create a database that is similar to the hierarchical database but with more flexibility and less defaults. The original and existing hierarchical database has one owner file linked strictly to one member file, reading a ladder affect that restricted the database to find relationships outside of its category. The Relational Model tool, not only to store information, but to access it as well. Relational databases are organized as tables.

The beauty of a table is that the information can be accessed or added without reorganizing the tables. A table can have many records and each record can have many fields. A relational database (3RD) is a collective set of multiple data sets organized by tables, records and columns. Reds establish a well-defined relationship between database tables. Tables communicate and share information, which facilitates data search ability, organization and reporting. Relational databases use a program interface called SQL (Standard Query Language). SQL is currently used on practically all relational databases.

Relational databases are extremely easy to customize to fit almost any kind of data storage. Relations can easily be created for items for sale, employees in a company, etc. Reds use Structured Query Language (SQL), which is a standard user application that provides an easy programming interface for database interaction. 3RD is derived from the mathematical function concept of mapping data sets and as developed by Edgar F. Cod. Tables are sometimes called a relation. It should be noted that every record (group of fields) in a relational database has its own primary key.

A primary key is a unique field that makes it easy to identify a record. Reds organize data in different ways. Each table is known as a relation, which contains one or more data category columns. Each table record (or row) contains a unique data instance defined for a corresponding column category. One or more data or record characteristics relate to one or many records to form functional dependencies. These re classified as follows: One to One: One table record relates to another record in another table. One to Many: One table record relates to many records in another table.

Many to One: More than one table record relates to another table record. Many to Many: More than one table record relates to more than one record in another table. 3RD performs “select”, “project” and “Join” database operations, where select is used for data retrieval, project identifies data attributes, and Join combines relations. Reds have many other advantages, including: Easy extendibility, as new data may be added without modifying existing records. This is also known as scalability. New technology performance, power and flexibility with multiple data requirement capabilities.

Data security, which is critical when data sharing is based on privacy. For example, management may share certain data privileges and access and block employees from other data, such as confidential salary or benefit information. Accessing Information with a Database While storing data is a great database feature, many database users consider quick and simple information retrieval the most important. It is extremely easy to pull up information regarding an employee in a relational database. Relational databases also add the power of running queries.

Queries are requests to pull specific types of information and either show them in their natural state or create a report using the data. For instance, if someone had a database of employees that included tables over a certain amount. No matter what kind of information is stored on a database, queries can be created with SQL to help answer important questions. Storing a Database Databases can be very small (less than 1 MBA) or extremely large and complicated (terabytes as in many government databases). However, all databases are usually tore and located on hard disks or other types of storage devices and are accessed via computer.

Large databases may require separate servers and locations, however many small databases can fit easily as files located on the computer’s hard drive. Securing a Database Obviously, many databases store confidential and important information that not Just anyone can easily access. Many databases require passwords and other security features in order to access the information. While some databases can be accessed via the Internet through a network, other databases are closed systems and can only be accessed on site.

INTERNET TECHNOLOGIES During our evolutionary Journey from Homo erects to Neanderthal and then to Homo sapiens, we have come a long way. Because of our continuous quest for more amenities and better standard of living, we have been able to invent and discover many new things. The nineties witnessed a major revolution with the invention of the first electronic digital computers. Till then, the term Internet was practically unknown to most people. However, today, the Internet has become the most powerful tool for people around the world.

With the advent of Internet, our earth has virtually reduced n size and has attained the form of a global village. The Internet can be explained as a network of computers, designed to receive and send data in the form of e-mails, blobs, websites, etc. To put it simply, it can be likened to a super-massive server, armed with a plethora of information which is used by billions of people simultaneously. The Internet is basically a network that connects other, smaller networks. All modern technologies are connected by the Internet, thereby leaving no stone unturned. This digital world can be a playground for some and a battlefield for others.

The Internet has become an indispensable business tool, which has helped bring the world closer. Receiving news from across the world, accessing knowledge resources, and shopping online are simply a click away. The Internet has tremendous potential and a lot to offer in terms of services. However, like every other innovation in science and technology, the Internet comes with its own advantages and disadvantages, which have been discussed in this Puzzle article. Advantages of the Internet Faster Communication The Internet has been mankind’s greatest means of communication yet.

Newer innovations are only making it faster and more reliable. Today, we can initiate real- time communication with someone who is in another part of the world. Of video conferencing, chat and messenger services. With the help of these services, the geographically fragmented countries have come together to form a community that is able to share its thoughts on global issues, that affect each and every one of us. The Internet has given us a common platform and medium through which we are able to explore other cultures and ideologies.

Abundant Information Resources The Internet is a treasure trove of information; which offers knowledge on any given epic under the sun. Search engines make information accessible on various subject matters such as, government law and services, trade fairs and conferences, market information, new innovations and technical support, and even dispense advice on love and relationships matters. It has become common practice to seek assistance from the web in order to research and gather resources for homework, office presentations, and supplement ones own research.

The web also updates news about the latest breakthroughs in the field of medicine, technology, and other domains of science. Numerous websites such as America’s Doctor, have made it possible to seek online advice from specialist doctors without having to actually fix an appointment. Inexhaustible Education The Internet has become an essential propagator of knowledge, both through free as well as paid services. The credibility of this form of education and whether it is safe, secure, and trustworthy, is usually proven through the quality and authenticity of content presented by each website.

The World Wide Web has become a remarkable avenue for the academically unprivileged, to amass greater knowledge and know-how on subjects. The entire scope of homecomings has expanded because of increased accessibility to videos of teachers giving lectures, showing diagrams and explaining concepts, much like a real classroom. Nonprofit organizations too have opened websites that seek volunteers and donations in order to help the ones in need. There are also sites like Wisped, Coursers, Babble, Archive, and Teachers, among others, that have dedicated themselves to the art of imparting knowledge to people of all age groups.

Entertainment for Everyone Entertainment is one of the foremost reasons why people prefer surfing the Web. In fact, the Internet has gained much success by marketing for several multifaceted entertainment industries. Finding the latest updates about celebrities and exploring lifestyle websites have become day-to-day activities of many Internet consumers. On the other hand, even celebrities are using the Internet effectively for promoting their cause and for keeping their fans happy. Indeed, online gaming has tasted dramatic and phenomenal success because of its ever-increasing demand throughout the world.

Social Networking and Staying Connected One cannot imagine a social life without Backbone or Twitter. These portals have become our means to stay connected with friends and family, and stay in touch with the latest happenings in the world. Social networking has also evolved as a great medium to connect with like-minded individuals and become a part of interesting groups and communities. Apart from finding long-lost friends, the Internet also makes it easier to search and apply for Jobs and business opportunities on forums and communities. There are public chat rooms where users can meet new people.

For those who are single, the Internet also provides the option to select a suitable dating partner through secure inline profiles that can be filtered as per personal preferences. Online Services and E-commerce Thanks to numerous monetary services, we can perform all our financial transactions online. We can book tickets for a movie, transfer funds, pay utility bills and taxes without having to leave our homes or offices. Travel websites for instance, offer quick booking schemes and plan itineraries as per the preferences of their clients.

E-commerce is used for all type of business dealing that involves the transfer of money through the Internet. Online transaction of money has become the norm with almost all kinds of business. E-commerce, with its vast reach over a variety of products and services, makes it possible to have the client’s orders delivered at their doorsteps. Websites such as eBay allow customers to bid, buy, sell, and even auction products online. Disadvantages of the Internet Theft of Personal Information The use of Internet for banking, social networking, or other services, often makes our personal information vulnerable to theft.

There are no fail-proof ways to securing names, account numbers, addresses, photos, and credit card numbers from being stolen or misused by thieving websites and individuals. Unscrupulous hackers can access our sensitive information through unsecured connections by planting pushing software. Needless to say, the damage caused by having our identities misused and our accounts broken into, is often irreparable and most of all, embarrassing. Spamming Spamming refers to sending unwanted e-mails, which serve no purpose and needlessly obstruct the computer system.

Such illegal activities can be very frustrating as it makes it slower to access our email accounts and makes the entire service unreliable for consumers. Advertisements. This can prove to be increasingly perplexing, as it keeps getting axed with our more important emails. Fortunately, email service providers often have security systems in place to guard against spamming. Fortunately, it is possible to report an email as spam, so that all emails from the same email id or IP address, are blocked. Mallard Threats One of the most annoying problems with the Internet is the ease with which any mallard can infect our computers.

Internet users are often plagued by virus attacks that harm their computers and important files. Virus programs are inconspicuous and may get activated simply by clicking a seemingly harmless link. Computers unconnected to the Internet are extremely prone to IP targeted virus attacks that may end up crashing the system completely. Internet virus can be of three types. The first type of virus affects files and goes directly for a particular file or file type. The second type harms system and executable boot files. These can be particularly nasty, as they can effectively stop the computer from starting again.

Lastly, there’s the macro virus, which is the most common as well as the most harmless of them all. The macro virus simply keep changing things like symbols on word files. The type of virus that can replicate and bread itself is known as worms. When a virus is disguised as something else, it’s known as a Trojan. Age-inappropriate Content Pornography and age-inappropriate content is perhaps the biggest disadvantage of the Internet. The worst being underage porn, which is largely rampant in the deeper parts of the web.

It is the lack of control over the distribution and unrestricted access of pornographic material, that is detrimental to children. All that parents can do, is lock harmful sites and monitor the sites viewed by their children. Pornography is not Just frowned upon by most societies, it’s also banned by some. The Internet makes uploading shocking content so easy, that we end up coming across inappropriate words and images, despite not wanting to. Social Isolation, Obesity, and Depression The biggest problem with having the Internet is, its ability to create rifts between the real and virtual world.

The virtual world can often seem so alluring that once hooked, going back to real life seems daunting. There is an addiction for everything that pertains to the web and that includes excessive surfing, online gambling, social networking, and gaming addiction. There are now psychiatric clinics and doctors that specifically cater to resolving the robbers created by the Internet. These addictions create both physical as well as mental issues that can lead to health complications if left unattended.

It is ironic that, while it is easy to find plenty of online support for agoraphobia, the Internet itself can be a big cause or trigger for it. The link between obesity and the Internet is rather easy to understand. The more list of physical and emotional maladies, is depression. Since all problems are so deeply linked with one another and with the Internet, it isn’t uncommon for people to be afflicted with multiple issues. Recent studies and research have gone deep enough to actually differentiate between compulsive Internet use and excessive Internet use.

Furthermore, thanks to smartness, holding a simple face-to-face conversation seems out of the ordinary as compared to chatting online. Thus, even though the Internet has the potential to make our lives simple and convenient, it also holds the power to wreak havoc. Its influence on us is mostly dictated by the choices we make while being online. With prudent use, we can manage to harness its unlimited potential and steer clear of its adverse effects. The Internet offers a world of information in one place. It is a helpful tool in communicating and researching all different subjects.

It is also a great way for students to use computers with proper supervision. Yet using the Internet in an educational system can be controversial. Some of the disadvantages include students giving out too much information about themselves, sites too commercialese with little educational value, and access to material that parents might not want their children exposed to. However, teachers and students have seen many benefits. The Internet helps students develop their computer skills. It can also help students with their writing skills. In some forms, the Internet can help students with critical thinking skills.

Students are faced with more information than they could ever use or need. This requires them to sort through the information and decide what is most important and relevant. With e-mail, students can have contact with other students around the world studying the same things they are. The Internet can be a huge source for student trying to look up information for a college project or do homework. It also eliminates barriers for handicapped students who may have trouble getting to a library. It allows all students to have access to information whether or not their Emily has a set of encyclopedias.

The Internet allows students to read the latest news of a certain subject they are studying. If they are studying Indian politics they can do a news search and find out what is happening in the world of politics at that very moment. This can help them connect what they are learning to the real world. It can also keep them interested in a subject. Students may have longer attention spans with technology than with other forms of traditional learning. Students will have to use the computer for research in college, in their Jobs and their everyday ivies.

The Internet is a way of life for almost everyone now. Using it in a classroom is one of the best and safest ways to help them learn about this tool. The Internet is an added bonus for teachers looking for more information on subjects for giving lectures. It allows them to efficiently communicate with teachers through email. The Internet is a powerful tool for assisting students and educators with conducting research. Going to a library and searching through a card catalog by hand can be laborious and inefficient compared to searching for the same information on a computer.

Many college offer online library systems which allow students to find information on books using lab computers, or to access databases of scholarly in higher education is its role in e-Learning. E-Learning uses course materials that exist entirely on a computer or the Internet. Some schools offer courses that are entirely e-learning based, meaning all texts, assignments, quizzes and tests are accessible online and no face-to-face meetings are required. E-learning allows students with limited mobility or inflexible schedules to take courses and study at times that are convenient for them.

E-learning also allows students to learn at different rates; one student could go through a certain course and finish it in half the time of another student. Many brick-and-mortar colleges and universities offer online courses or have courses with aspects of e-learning, such as online quizzes and exams. Conclusion Hence we conclude that, Internet is a most powerful educational tool for teaching Learning . Internet is useful for self-study to student. Internet gives to student a lot of information for student to achieve goal. Internet could also be used for assignment and the progress of student.