What Is Rdbms Ordbms And Oodbms Information Technology Essay

What Is Rdbms Ordbms And Oodbms Information Technology Essay A set of computer programs which controls the formation, preservation, and the use of database with computer as a platform is called a database management system (DBMS). The control of organization-wide database development in the hands of database administrators (DBAs) is permitted by the database management system. It helps the use of integrated collection of data and files and also easily permits the access of the same database to different user application programs. The database models like network model or relational model can be used by the DBMS. Another feature of the DBMS is allows users and other software to store and get back data in a structured way in large systems. The users can write simple question in query language to retrieve information instead of writing computer programs. Fourth-generation programming language (4GLs) and other application development features provided by DBMS are very helpful to specify the logical organization for database and access and use the information within a database. Relational Data Base Management System (RDBMS) The abbreviation form of Relational Data Base Management System is RDBMS. The structure of RDBMS is database tables, fields and records. Each RDBMS table consists of database table rows and each database table row consists of one or more database table fields. RDBMS is used by main frame, midrange and microcomputers. MS SQL Server, DB2, Oracle and MySQL are the most popular RDBMS. The data are stored in the form of tables which might be related by common fields. The data stored in the database table are manipulated by the rational operators given by RDBMS. SQL is the database query language in most RDBMS. Why RDBMS? We will use the terms tables and relations interchangeably. In a RDBMS, the data is logically perceived as tables. _ Tables are in logical data structures that we assume hold the data that the database intends to represents _ And tables are not physical structures. _ Each table have a unique table name There are advantages and as well as disadvantages in the RDBMS. The advantages of RDBMS are Fast and easy to pop out data as relation among entities is well defined More secure and normalization Problems are avoided when two things are processed at the same time data can be managed in proper manner Accuracy The disadvantages on the other hand are A professional is needed to deal with Proper training is required Need software and hard ware The model is not easy to the end user to run quires Object Relational Database Management System (ORDBMS) The object relational database management system is known as a database management system which is alike to a relational database, but with an object oriented database model. This system supports classes, objects and inheritance directly in database schemas and in the query language. Besides, extension of the data model with custom data type and methods are supported by ORDBMS. The well-organized management from a limited set of data types is focused in traditional RDBMS but object relational DBMS on the other hand permits web sites development experts to join their own data types and methods. Advantages of ORDBMS: Large storage capacity is ensured in Object Relational Database Management Systems which benefits for the web based development. Reasonably quick access speed Massive scalability of ORDBMS is beneficial. Outstanding manipulation power of object databases is boasted in ORDBMS APIs and server subsystems are added to support object functionality. The database engine is completely redesigned A new object-oriented layer is added to support rich data types Disadvantages of ORDBMS ORDMBS fails in High speed internet applications. The IDC opines that the ORDBMS market has the possibility to exceed the size of ODBMS in the next two years time in web based development Object Oriented Database Management system (OODBMS) Object Oriented Database Management system is the most excellent alternative to resolve impedance mismatch causing in the use of Relational Database Management System as objects have to be mapped to table. Database management is combined with object oriented programming concepts by the object oriented database management system. The principles of database management such as isolation, durability, consistency and atomicity and the object oriented programming concepts consist of of inheritance, encapsulation and polymorphism. The mixture of these ideas permits easiness in the management of large number of data, results in system reliability and guarantees support for query languages. Therefore, from the description given above it can be concluded that an OODBMS is not only a database management system but also a complete object oriented development setting. Software development companies use OODBMS as an alternative because it follows intelligibility while objects are accessed in the database. The Main objective of the OODBMS is to give consistent, data independent, secure, controlled and extensible data management services to support the object-oriented model. They were created to handle big and complex data that relational databases could not. The most main characteristic is the joining of object-oriented programming with database technology, which provides an integrated application development system. Object-oriented programming results in 4 main characteristics: inheritances, data encapsulation, object identity, and polymorphism. Object Identity, Object Structure, and Type Constructors Object Identity An OO database system provides a unique identity to each independent object stored in the database. This unique identity is typically implemented via a unique, system-generated object identifier (OID). The OID cab is assigned to program variables of the appropriate type when needed. The main property required of an OID is that it be immutable; that is, the OID value of a particular object should not change. This preserves the identity of the real-world object being represented. Merits of OODBMS over RDBMS The impedance mismatch is completely cancelled out in OODBMS and on the other hand in a relational database system a problem is always faced by a custom software development company. There was lot of wastage of time in RDBMS while objects had to be mapped with tables and the table mapped with objects. In the RDBMS, problems have to be faced by the users when identifying the records and they have to make sure that no two records have the same primary key. In the OODBMS this problem is completely avoided by its unique OIDs. OODBMS can deal with complex data than RDBMS as in ODBMS, a large class able to hold lot of intermediate sized classes, which can keep even more medium sized classes. The database management system maintains the connection between objects and the constraints on objects in an object oriented database, which means, the objects themselves. They permit support of complex application which is not supported by the other models. The programmability and performance, improve navigational access, and simplify concurrency control are improved by the object oriented database. The risks linked with the referential integrity are reduced in OODBMS and it gives an enhanced user metaphor than the relational model. Object oriented database can store both complex component and large structure. The large objects in object oriented database do not need to be broken apart and reassemble by application. Therefore object oriented data base do not suffer performance degradation. RDBMS does not allow the nested structure. These category of applications widely found in CAD/CAE, aerospace, etc. But these applications are easily supported in OODBMS. Besides, it is better to deal with the complex structure in the form of objects rather than table, tuples and records in RDBMS. Limited numbers of data types such as integer and string and limited number of built in operations are available in the relational database management system. This database management system is suitable for simple and few number of data types. The OODBMS on the other hand are appropriate for application where the relationships among elements in the database carry the key information. Conclusion According to the report we can takes some con-clusions regarding RDBMS and OODBMS: †¢ Relational databases have as their objective to ensure data independence ie> Normalized data is separated from processing and the processing corresponding to satisfy-ing informational requirements need not be totally pre-defined, thus accepting ad-hoc re-quirements too. †¢ Object oriented databases have as their main objective encapsulation, being stored together with the data and the methods. They are inseparable. It is said that we have to do with an independence of classes and not with an independence of data. †¢ An OODBMS and not an RDBMS is needed while in the reference applications we have to do with complex data. †¢ The object oriented database mar-kets will continue to develop, but they will still (represent) only a fraction of the traditional databases. †¢ It is appreciated that RDMSs hold the largest part of the largest part of the data-bases. But the prospect is that they will still co-exist for a long time future with the OODBS. ORDBMS complicates database design due to its new richness. There are more alternative designs that can be used to represent a particular situation, and it is not always obvious which to pick. Unthinkingly applying some of these features, such as the COLLECTION columns, create problems.

Sadies perspective paper

I never thought of before. Brainstorm Of Mice and Men John Steinbeck Crooks African American and physically disabled Elementally challenged Curly wife how women were treated Thesis Statement The author, John Steinbeck in his book Of Mice and Men helped my understanding and interpretation of how women were treated in the time that this b ask was written through the character Curler's wife.They were lonely, misunderstood and mi striated. Title Brainstorm Woman's problem Woman's woes Outline for UP Essay Introduction Hook (Quote, universal Statement, Question, etc. ) to get your reader interested in the general topic Have you ever been judged by the way you look or what you do? And as a result you w ere mistreated.Transition/ Smoothing Sentence(s) to show the connection between your hook and your primary focus of your essay Thesis Statement to narrow your focus to the point you are arguing (sometimes with t ere mall points provided to clarify your focus) The author, John Steinbeck in hi s book Of Mice and Men helped my understanding and interpretation of how woman were treated in the time that this book was written through the character, Curlers wife.They were lonely, misunderstood and mistreated. 1st Main Idea: lonely Topic Sentence Woman In the asses were lonely like Curler's wife. Supporting Details/ Evidence (including examples and, if a literary analysis essay, quotes)

Take a Stand - 1085 Words

Name: Course: Date: Instructor: Topic 7 Assignment: Journal Compilation from Weeks 1-6 Reflections on Planning for a Successful Graduation Life Road Map Directions: You will be starting this assignment in week 1 (Topic 1) and will continue to build and complete this assignment each week until you submit the final product in week 7 (Topic 7). There are 2 parts to this assignment; Part One will be responding to a variety of different writing prompts relating to the topics and objectives of the course. This part of the assignment should be completed one week at a time. There are 3-4 prompts associated with each of the first 5 weeks of class. You will not turn this assignment in until week 7, but there are specific DQ’s†¦show more content†¦How will prioritizing your academic responsibilities contribute to your college success as well as prepare you for your career path? Part Two: To be completed in Weeks 6 through 7 Directions: Please respond to the following 4 prompts in paragraph form; 250 words per prompt. Use specific examples to support and enhance each response. (The spacing can be manipulated as you require more room for your responses if needed.) 1. Writing Prompt #1: Personal Background Respond to the following questions within your response: Where are you from? How have your background and your family values shaped who you are today? What are some of your greatest strengths and weaknesses? Describe your schooling experience prior to GCU? What did you like most? What did you dislike? Who was your favorite teacher and why? 2. Writing Prompt #2: Goals and Planning Respond to the following questions within your response: How, when, and why did you decide to enroll at GCU? What are some expectation(s) you wish to gain from attending GCU? What are your academic goals, personal goals, and professional goals? 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Confidence Interval for the Difference of Two Population Proportions

Confidence intervals are one part of inferential statistics.  The basic idea behind this topic is to estimate the value of an unknown population  parameter by using a statistical sample.  We can not only estimate the value of a parameter, but we can also adapt our methods to estimate the difference between two related parameters.  For example we may want to find the difference in the percentage of the male U.S. voting population who supports a particular piece of legislation compared to the female voting population. We will see how to do this type of calculation by constructing a confidence interval for the difference of two population proportions.  In the process we will examine some of the theory behind this calculation.  We will see some similarities in how we construct a confidence interval for a single population proportion as well as a confidence interval for the difference of two population means. Generalities Before looking at the specific formula that we will use, lets consider the overall framework that this type of confidence interval fits into.  The form of the type of confidence interval that we will look at is given by the following formula: Estimate /- Margin of Error Many confidence intervals are of this type. There are two numbers that we need to calculate.  The first of these values is the estimate for the parameter.  The second value is the margin of error.  This margin of error accounts for the fact that we do have an estimate.  The confidence interval provides us with a range of possible values for our unknown parameter. Conditions We should make sure that all of the conditions are satisfied before doing any calculation. To find a confidence interval for the difference of two population proportions, we need to make sure that the following hold: We have two simple random samples from large populations.  Here large means that the population is at least 20 times larger than the size of the sample. The sample sizes will be denoted by n1 and n2.Our individuals have been chosen independently of one another.There are at least ten successes and ten failures in each of our samples. If the last item in the list is not satisfied, then there may be a way around this.  We can modify the plus-four confidence interval construction and obtain robust results.  As we go forward we assume that all of the above conditions have been met. Samples and Population Proportions Now we are ready to construct our confidence interval.  We start with the estimate for the difference between our population proportions. Both of these population proportions are estimated by a sample proportion.  These sample proportions are statistics that are found by dividing the number of successes in each sample, and then dividing by the respective sample size. The first population proportion is denoted by p1.  If the number of successes in our sample from this population is k1, then we have a sample proportion of k1 / n1. We denote this statistic by  pÌ‚1.  We read this symbol as p1-hat because it looks like the symbol p1 with a hat on top. In a similar way we can calculate a sample proportion from our second population.  The parameter from this population is p2.  If the number of successes in our sample from this population is k2, and our sample proportion is  pÌ‚2 k2 / n2. These two statistics become the first part of our confidence interval. The estimate of p1 is pÌ‚1.  The estimate of p2 is pÌ‚2.  So the estimate for the difference p1 - p2 is pÌ‚1 - pÌ‚2. Sampling Distribution of the Difference of Sample Proportions Next we need to obtain the formula for the margin of error.  To do this we will first consider the   sampling distribution of  pÌ‚1  . This is a binomial distribution with probability of success p1 and  n1 trials. The mean of this distribution is the proportion p1.  The standard deviation of this type of random variable has variance of p1  (1 - p1  )/n1. The sampling distribution of pÌ‚2 is similar to that of pÌ‚1  .  Simply change all of the indices from 1 to 2 and we have a binomial distribution with mean of p2 and variance of p2 (1 - p2 )/n2. We now need a few results from mathematical statistics in order to determine the sampling distribution of pÌ‚1 - pÌ‚2.  The mean of this distribution is p1 - p2.  Due to the fact that the variances add together, we see that the variance of the sampling distribution is p1  (1 - p1  )/n1 p2 (1 - p2 )/n2.  The standard deviation of the distribution is the square root of this formula. There are a couple of adjustments that we need to make.  The first is that the formula for the standard deviation of pÌ‚1 - pÌ‚2 uses the unknown parameters of p1 and p2.  Of course if we really knew these values, then it would not be an interesting statistical problem at all.  We would not need to estimate the difference between p1 and  p2..  Instead we could simply calculate the exact difference. This problem can be fixed by calculating a standard error rather than a standard deviation.  All that we need to do is to replace the population proportions by sample proportions.  Standard errors are calculated from upon statistics instead of parameters. A standard error is useful because it effectively estimates a  standard deviation.  What this means for us is that we no longer need to know the value of the parameters p1 and p2.  .Since these sample proportions are known, the standard error is given by the square root of the following expression: pÌ‚1 (1 -  pÌ‚1 )/n1   pÌ‚2 (1 -  pÌ‚2 )/n2. The second item that we need to address is the particular form of our sampling distribution.  It turns out that we can use a normal distribution to approximate the sampling distribution of  pÌ‚1  - pÌ‚2.  The reason for this is somewhat technical, but is outlined in the next paragraph.   Both  pÌ‚1 and  pÌ‚2   have a sampling distribution that is binomial.  Each of these binomial distributions may be approximated quite well by a normal distribution.  Thus pÌ‚1  - pÌ‚2 is a random variable.  It is formed as a linear combination of two random variables.  Each of these are approximated by a normal distribution.  Therefore the sampling distribution of pÌ‚1  - pÌ‚2 is also normally distributed. Confidence Interval Formula We now have everything we need to assemble our confidence interval.  The estimate is (pÌ‚1 - pÌ‚2) and the margin of error is z* [ pÌ‚1 (1 -  pÌ‚1 )/n1   pÌ‚2 (1 -  pÌ‚2 )/n2.]0.5.  The value that we enter for z* is dictated by the level of confidence C.  Ã‚  Commonly used values for z* are 1.645 for 90% confidence and 1.96 for 95% confidence.  These values for  z* denote the portion of the standard normal distribution where exactly  C percent of the distribution is between -z* and z*.   The following formula gives us a confidence interval for the difference of two population proportions: (pÌ‚1 - pÌ‚2) /- z* [ pÌ‚1 (1 -  pÌ‚1 )/n1   pÌ‚2 (1 -  pÌ‚2 )/n2.]0.5