Relational Algebra

In: Computers and Technology

Submitted By Gurpreet258
Words 344
Pages 2
The relational algebra is a theoretical language with operations that work on one or more relations to define another relation without changing the original relation. Thus, both the operands and the results are relations; hence the output from one operation can become the input to another operation.
This allows expressions to be nested in the relational algebra. This property is called closure. Relational algebra is an abstract language, which means that the queries formulated in relational algebra are not intended to be executed on a computer. Relational algebra consists of group of relational operators that can be used to manipulate relations to obtain a desired result. Knowledge about relational algebra allows us to understand query execution and optimization in relational database management system.
Role of Relational Algebra in DBMS
Knowledge about relational algebra allows us to understand query execution and optimization in relational database management system. The role of relational algebra in DBMS is shown in Fig. 3.1. From the figure it is evident that when a SQL query has to be converted into an executable code, first it has to be parsed to a valid relational algebraic expression, then there should be a proper query execution plan to speed up the data retrieval. The query execution plan is given by query optimizer.
Relational Algebra Operations
Operations in relational algebra can be broadly classified into set operation and database operations. Unary and Binary Operations
Unary operation involves one operand, whereas binary operation involves two operands. The selection and projection are unary operations. Union, difference,
Cartesian product, and Join operations are binary operations:
Unary operation operate on one relation
Binary operation operate on more than one relation
Selection Operation
The selection operation works…...

Similar Documents

Algebra

...Preparation of income statement, balance sheet and statement of cash flows: Accounting for specialized items: Property, Plant & Equipment, bad debts; provisions; financial instruments; leases; employee benefits; income taxes; revenues,; foreign currency transactions etc.;Accounting for mergers and consolidations; IFRS vs GAAP; Financial statement analysis 3. Cost and Management Accounting: Cost concepts; Job-order costing vs process costing;ABC Costing; Marginal costing vs absorption costing: CVP analysis; Relevant costs: special order, make or buy decisions; ROA, residual income and economic value added; Standard costing and variance analysis; EOQ and linear programming 4. Quantitative Methods and Business Mathematics: Algebra and logarithm; Series and progressions; Probability, confidence intervals and testing; Measures of central tendency and measures of dispersion; Simple and compound interest: compounding and discounting;Differentiation and integration; Regression and correlation 5. Business Management: Vision, mission and strategy; Human resource management : recruitment and retention, performance measurement and development, compensation, employee rations and ethics etc.; Marketing; Organizational culture, organizational change and effective communication; Business analyses: SWOT, PESTLE, balanced scorecard 6. Microsoft Excel 2003/2007/2010: Financial Model Development; Visual Basic for Application(VBA) development, Lookup; Solver;......

Words: 764 - Pages: 4

Relational Databases

...Relational Database: Design This paper evaluates four similar web databases and concludes with an overview of considerations for designing web databases. The web databases reviewed are: (a) the Academy of Motion Pictures and Arts (Academy, 2013), (b) IMDb (IMDb, 2013), (c) Complete Index to World Film (Complete Index, 2013), and (d) Labor Film Database (Labor Film, 2013). Table 1 summarizes each database in terms of purpose, target audience, functions, and usability. Table 1 Summary of Web Database Reviews Academy IMDb CITWF Labor Films Purpose • Digital artifact preservation for movie industry • Movie industry research • Search vast amounts of information on just about any film, game or actor • Search fair amount of information on just about any film in the world • Educate • Research Audience • Journalists • Filmmakers • Students • Hobbyists • General public • Film buffs • Journalists • Hobbyists • Gamers • Students • Researchers • Film buffs • Hobbyists • Researchers • Activists • General public Functions • Basic and advanced searches • Six advanced query functions using: fill-in-the-box, check-a-square, and pre-filled drop-down database values • Collects information in user-defined lists. • Watch lists • Simple Search: user selects film or person from a drop-down box and enters a search phrase • Advanced Search: user builds multiple-condition • One-size-fits-all search via a drop-down box of extensive search categories • On-demand......

Words: 2130 - Pages: 9

Algebra

...Week four assignment MAT221: introduction to algebra Thurman Solana July 7, 2013 Below we will go through a few equations for this week’s assignment. I will show my knowledge of how to properly find the correct answers to each problem. As well as showing my knowledge of the words: Like terms FOIL Descending Order Dividend and Divisor. Compound semiannually On page 304 problem #90 states “P dollars is invested at annual interest rates r for one year. If the interest rate is compounded semiannually then the polynomial p(1+r2) represents the value of investment after one year. Rewrite the problem without the equation.”(Algebra) For the first equation p will stand for 200 and r will stand for 10%. First I need to turn the interest rate into a decimal. 10%=0.1. Now I can rewrite the equation.2001+0.122. Now that I have my equation written out I can start to solve. I start by dividing 0.1 by 2 to get 0.05. Now I can rewrite 2001+0.052. First I add the 1 and 0.05 giving me 1.05 to square. Any number times itself is called squaring. So now we square (1.05)*(1.05)=(1.1025). Again we rewrite our equation 200*1.1025=220.5. Now we can remove the parentheses leaving us with an answer of 220.5. The answer for this first part of 2001+0.0122=220.5. Second Part On this second part let p stand for 5670 and r will stand for 3.5%. Again I start by turning my percentage into a decimal 3.5%=0.035. Now that we have our decimal we can write out our equation......

Words: 594 - Pages: 3

Relational Algebra

...Edited by Foxit PDF Editor Copyright dddddd (c) by Foxit Software Company, 2004 For Evaluation Only. Edited by Foxit PDF Editor Copyright (c) by Foxit Software Company, 2004 For Evaluation Only. Computer Science Volume 1 Silberschatz−Korth−Sudarshan • Database System Concepts, Fourth Edition Front Matter 1 1 11 11 35 35 36 87 140 140 141 194 229 260 307 307 308 337 363 393 393 394 446 494 529 563 563 564 590 637 Preface 1. Introduction Text I. Data Models Introduction 2. Entity−Relationship Model 3. Relational Model II. Relational Databases Introduction 4. SQL 5. Other Relational Languages 6. Integrity and Security 7. Relational−Database Design III. Object−Based Databases and XML Introduction 8. Object−Oriented Databases 9. Object−Relational Databases 10. XML IV. Data Storage and Querying Introduction 11. Storage and File Structure 12. Indexing and Hashing 13. Query Processing 14. Query Optimization V. Transaction Management Introduction 15. Transactions 16. Concurrency Control 17. Recovery System iii VI. Database System Architecture 679 679 680 705 750 773 773 774 810 856 884 Introduction 18. Database System Architecture 19. Distributed Databases 20. Parallel Databases VII. Other Topics Introduction 21. Application Development and Administration 22. Advanced Querying and Information Retrieval 23. Advanced Data Types and New Applications 24. Advanced Transaction Processing iv Silberschatz−Korth−Sudarshan:......

Words: 301237 - Pages: 1205

Algebra

...sentence including an equal sign. Equivalent fractions - fractions equal to one another, even though they may have different denominators. Even - a number that is divisible by 2. Exponent - in the expression x to the second power, the exponent is 2; x will be multiplied by itself two times. Expression - mathematical incomplete sentence that doesnt contain an equal sign. Factor - if a is a factor of b, then b is divisible by a. Factorial - operation that multiplies a whole number by every counting number smaller than it. Formula - rule or method that is accepted as true and used over and over in common applications. Fraction - ratio of two numbers representing some portion of an integer. Fundamental theorem of algebra - guarantees that a polynomial of degree n, if set equal to 0, will have exactly n roots. Function - a relation whose inputs each have a single, corresponding output. Graph - plotted figure in a plane. Greatest common factor - the largest factor of two or more numbers or terms. Grouping symbols - elements like parentheses and brackets that explicitly tell you what to simplify first in a problem. Horizontal line test - tests the graph of a function to determine whether or not its one to one. Hypotenuse - longest side of right triangle. i - The imaginary value square root of -1. Identity element - the number(0 for addition, 1 for multiplication) that leaves a numbers value unchanged when the corresponding operation...

Words: 3052 - Pages: 13

Relational Leadership

...Running Head: In Support of Relational Leadership In Support of Relational Leadership By Gail S. Pasley Submitted in partial fulfillment of The requirements for the degree of Masters of Arts Human Resources Development Under the direction and Guidance of Dr. Barbara Seifert, Ph.D. Human Resources Professor Webster University Orlando Metropolitan Campus April 12, 2011 In Support of Relational Leadership What does Winston Churchill, Martin Luther King, Jr., Margaret Thatcher or John F. Kennedy have in common? The answer appears to be obvious—they are great leaders who possess great intellect, persuasive ability, charisma, etc. And, most of us would even dare to say that Adolph Hitler and Osama Bin Laden were also great leaders—after all, look at the empires they built, and the great following they commanded. Jim Jones, leader of the People’s Temple was hailed by many as a great spiritual leader until he led a “revolutionary suicide”, that became known as the Jonestown Massacre in 1978, which left nine hundred and eighteen people dead (Rosenberg, para. 1). What separate these two groups of leaders from the other? What truly makes a great leader? Or is the idea of the great leader, in the words of Levi and Ritti (2002), “one of America’s most cherished myths.” Even with this assertion Levi and Ritti do not totally deny the influence of leadership in the success of an organization, but cautions that it is challenging to measure its efficacy......

Words: 3317 - Pages: 14

Algebra

...SUBDOMAIN 212.1 - NUMERACY, ALGEBRA, & GEOMETRY Competency 212.1.2: Solving Algebraic Equations - The graduate solves algebraic equations and constructs equations to solve real-world problems. Introduction: An important element of learning is to connect mathematical concepts with physical concepts. Graphical representations of mathematical functions will allow you to visualize the meaning and power of mathematical equations. The power of computer programs and graphing calculators provide a more thorough connection between algebraic equations and visual representation, which will increase appreciation and understanding of mathematical language. In this task, you will be making connections between algebraic equations and graphical representations. You will use the following situation to complete your task: A man shines a laser beam from a third-story window of a building onto the pavement below. The path of the laser beam is represented by the equation y = –(2/3)x + 30. In this problem, y represents the height above the ground, and x represents the distance from the face of the building. All height and distance measurements are in feet. Task: A. Use the situation above to complete parts A1 through A5. 1. Find the x-intercept and y-intercept of the given equation algebraically, showing all work. 2. Graph the given equation. • Label each axis of the coordinate plane with descriptive labels. • Label each intercept as “x-intercept” or “y-intercept” and include the ordered pair. 3.......

Words: 521 - Pages: 3

Relational Databases

...Relational Databases Jason A. Mizener Professor Merkel Intro to Information Technology 17 August 2014 Relational Databases As technology as grown throughout the years, so has the information it utilizes. Early on databases were organized through the hierarchical model, which was the earliest representation of the parent-child structure (each parent can have multiple children, but each child can only have one parent). Shortly thereafter the network database model was incorporated to more effectively represent complex data relationships. Large amounts of data became better organized, which improved database performance. Additionally, the parent-child structure was improved to where children could now have multiple parents. Despite these advances, databases continued to grow increasingly cumbersome and complex, and further advances were necessary to keep everything manageable. The relational database, designed in 1970 by E. F. Codd, represented a major breakthrough in database technology for both designers and users alike. The relational model is very simple, yet very effective in concept. As strange as it may be to think, the relational database pioneered the concept of using tables to hold and organize data. An Excel spreadsheet is probably the most obvious example of a relational database that the end user can relate to today. Essentially, a relational database is the logical view, rather than the physical view, of information. (Carlos Coronel,......

Words: 1200 - Pages: 5

Relational Database

...Relational Model of Shared Data Banks Abstract How does one decide best practice for a database management design? Who has used mathematics and science as a basis to assist organizations with a baseline relational model for database management? Well for over the last forty years credit has been given to entrepreneur Edgar F. Codd. The evolution of relational databases remain ever changing, however the foundation laid by Cobb remains best practice for the vast majority of organizations. Simple principles defined in his writing “A Relational Model of Data for Large Shared Data Banks” exhibits pros and cons in comparison to other databases. Although databases range in size, durability, and ease all plays a significant role in an organization growth, success, and failure. Relational Model of Shared Data Banks The paper “A Relational Model of Data for Large Shared Data Banks”, written by E. F. Codd explains the advantages of a relational database model primarily in comparison to the tree-structure and network model. The author points out the importance of derivability, redundancy and consistency of relations within the relational model versus other prototypes. One of Cobb’s example cites, “The network model, on the other hand, has spawned a number of confusions, not the least of which is mistaking the derivation of connection for the derivation of relations” (Cobb, 1970, p. 377). Cobb’s overall goal is to make sure readers see how effective and how successful an organization...

Words: 516 - Pages: 3

Algebra

...Name: Taylor Harmon_________________________ Score: ______ / ______ Pre-Algebra Midterm Exam Solve the problems below. Show your work when applicable. 1. Write using exponents. (–4)(–4) -4^2 2. Simplify. Show your work. 513 +-3918 5x3+1/3 + -3 9/18 16/3 + -3 9/18 16/3 + -3 ½ 16/3 – 3x2+1/2 16/3 – 7/2 Least common denominator found is 6 16x2/3x2 – 7x3/2x3 32/6 – 21/6 = 11/6 11/6 = 1 5/6 3. What type of measurement would you use to describe the amount of water a pot can hold? Volume – gallons, liters 4. Estimate the sum of 9.327 + 5.72 + 4.132 to one decimal place. 19.2 5. State whether the number 91 is prime, composite, or neither. Composite. It can be divided by 7 or 13 6. What are the mean and the mode of the following set of data: 5, 12, 1, 5, 7 mean: 6 mode: 5 7. To measure the distance from the U.S. to Istanbul, Turkey you would most likely use __________. miles 8. What percent of 67 is 33? Round to the nearest tenth of a percent. 49.3% 9. An adult house cat could be about 1 ___________ high. foot 10. Write a number sentence for the model. Let one white tile equal +1 and one black tile equal –1. There are -14 black tiles and 6 of them become white tiles. -14+6=-8 11. Determine whether the statement is true or false. 94 is divisible by 3. false 12. State whether the number 97 is prime, composite, or neither. prime 13.......

Words: 389 - Pages: 2

Relational Leadership

...million training in situational leadersip and nearly 400 out of 500 fortune company implementing this model. Fernandez, C. F. and Vecchio, R. P. Situational Leadership Theory Revisited: A Test of an Across-Jobs Perspective, Leadership Quarterly, 8(1), p. 67 1997. One of the problems with this situational model of leadership is that it assumes that a leader can ascertain the maturity level of the subordinate in relation to the task in hand. [Strunz H., Dorsch M.,2001, page 146] . This may not be possible to achieve. Other disadvantages [pic] Transformational leadership Relational leadership Relational leadership theory is a relatively new concept. It focuses more and on the relationship than on the attributes of the leader. “Leadership is always dependent on the context, but thecontext is established by the relationships we value” (Wheatley, 1992, p. 144). The common relational model focuses on 5 components. It is a process orientated model with all the four remaining components being accomplished. It is a ‘purposeful’ leadership, which is ‘inclusive’ of all the people within a given group. It is achieved through positive purpose that ‘empowers’ those involved and is done ‘ethically’. Purposeful This involves clear defined social vision that is based in a common goal. Therefore it brings positive change. This is very different from an individual leader with their own personal vision. The social vision is described by Komives as one that all......

Words: 2379 - Pages: 10

Algebra

...What is Algebra? Algebra is a branch of mathematics that uses mathematical statements to describe relationships between things that vary over time. These variables include things like the relationship between supply of an object and its price. When we use a mathematical statement to describe a relationship, we often use letters to represent the quantity that varies, sisnce it is not a fixed amount. These letters and symbols are referred to as variables. (See the Appendix One for a brief review of constants and variables.) The mathematical statements that describe relationships are expressed using algebraic terms, expressions, or equations (mathematical statements containing letters or symbols to represent numbers). Before we use algebra to find information about these kinds of relationships, it is important to first cover some basic terminology. In this unit we will first define terms, expressions, and equations. In the remaining units in this book we will review how to work with algebraic expressions, solve equations, and how to construct algebraic equations that describe a relationship. We will also introduce the notation used in algebra as we move through this unit. History of algebra The history of algebra began in ancient Egypt and Babylon, where people learned to solve linear (ax = b) and quadratic (ax2 + bx = c) equations, as well as indeterminate equations such as x2 + y2 = z2, whereby several unknowns are involved. The ancient Babylonians solved......

Words: 1079 - Pages: 5

Premiere Products Exercise for Relational Algebra

...1. List the number and name of all sales reps. PROJECT Rep OVER (RepNum, LastName, FirstName) GIVING Answer 2. List all information from the Part table for part FD21. SELECT Part WHERE PartNum = 'FD21' GIVING Answer 3. List the order number, order date, customer number, and customer name for each order. JOIN Orders, Customer WHERE Orders.CustomerNum=Customer.CustomerNum GIVING Temp PROJECT Temp OVER (OrderNum, OrderDate, CustomerNum, CustomerName ) GIVING Answer 4. List the order number, order date, customer number, and customer name for each order placed by any customer represented by the sales rep whose last name is Kaiser. JOIN Orders, Customer WHERE Orders.CustomerNum=Customer.CustomerNum GIVING Temp1 JOIN Temp1, Rep WHERE Temp1.RepNum=Rep.RepNum GIVING Temp2 SELECT Temp2 WHERE Rep.LastName= ‘Kaiser’ GIVING Temp3 PROJECT Temp3 OVER (OrderNum, OrderDate, CustomerNum, CustomerName) GIVING Answer 5. List the number and date of all orders that were placed on 10/20/2013 or that were placed by a customer whose rep number is 20. SELECT Orders WHERE OrderDate= ‘10/20/2013’ GIVING Temp1 PROJECT Temp1 OVER (OrderNum, OrderDate) GIVING Temp2 JOIN Orders, Customer WHERE Orders.CustomerNum=Customer.CustomerNum GIVING Temp3 SELECT Temp3 WHERE RepNum= ‘20’ GIVING Temp4 PROJECT Temp4 OVER (OrderNum, OrderDate) GIVING Temp5 UNION Temp2 WITH Temp5 GIVING Answer 6. List the number and date of all orders that were placed on 10/20/2013 by a......

Words: 352 - Pages: 2

Relational Databases

...UNDERSTANDING THE RELATIONAL DATABASES Student’s Name Instructor’s Name Course Name 03/05/2016 RELATIONAL DATABASES Being a data administrator is to handle and organize the bulk of data masses for easy and convenient retrieval of the information at any point of time. I generally believe that compiling a bulk of data is very difficult task for anyone who has the responsibility to manage the information. Therefore, here we go through and understand the concept of relational databases and use of tables designed to manage the data for the problem cases in our daily life. A relational database is a defined group of data items systematized and controlled as a set of formally defined tables from which the collected and unmanageable data can be reassembled or accessed in various different techniques deprived of having to restructure the pre-arranged database tables (Rouse, n.d.). According to Codd (1982), “Relational processing entails treating whole relationships as operands. Its primary purpose is loop-avoidance, an absolute requirement for end users to be productive at all, and a clear productivity booster for application programmers” (p.298). It comprises of designed data tables that are connected together in some important way. For instance, consider an organization that offers items to clients. The organization keeps up a database of the items it offers. Every item has a one of a kind code so it can be uniquely recognized. The item database comprises of a table, and......

Words: 631 - Pages: 3

Algebra

...7.0208 6.2911 5.8357 6.00 19.3328 11.1021 8.4386 7.1643 6.4430 5.9955 Your assignment must follow these formatting requirements: Be typed, double spaced, using Times New Roman font (size 12), with one-inch margins on all sides. Check with your professor for any additional instructions. Include a cover page containing the tile of the assignment, the student’s name, the professor’s name, the course title, and the date. The cover page is not included in the required assignment page length. The specific course learning outcomes associated with this assignment are: Apply finance formulas and logarithms to amortize loans and calculate interest. Use technology and information resources to research issues in algebra. Write clearly and concisely about algebra using proper writing mechanics....

Words: 643 - Pages: 3