...Can a database contain two identical records without a negative effect on the integrity of the database? Why or why not? Data redundancy is a situation that occurs within database systems and involves the unintentional creation of duplicated data that is not necessary to the function of the database. While redundancy is often a desirable trait in some situations, this is not true when it comes to the function of a database. The presence of duplicated data can often have an adverse effect on the function of the system, resulting in returning information in response to system queries that is less than helpful. One of the key functions of data management identification of duplicated data and the removal of those duplications (Tatum, 2015). The potential for data redundancy is found in just about any type of database program. Programs that are considered flat, such as spreadsheets, and rely on manual entry of data are particularly susceptible to the duplication of information that may lead to complications when it comes to retrieving the information desired. Relational style databases, such as sales contact databases, often include processes that help to minimize the chances for unintentional duplication, such as the creation of two different contact files on the same contact associated with the same company. Even with the use of system checks to help reduce the incidence of data redundancy, there is still the potential for issues to occur, making it necessary to periodically engage...
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...Industrial Database Systems Management Student Name: | Department: | Student Number: | Sheet #1 Given the following file structure, answer problems 1 through 6. 1. How many records does the file contain, and how many fields are there per record? 2. What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure? 3. If you wanted to produce a listing of the file contents by last name, are code, city, state, or zip code, how would you later the file structure? 4. What data redundancies do you detect and how could these redundancies lead to anomalies? 5. Using two relational database tables, PROJECT and MANAGER, eliminate the redundancies discovered in problem 4. Make sure you use the naming conventions and connect the two tables through an appropriate link. 6. Create the relational schema to show how the two database tables in problem 5 are linked. Given the following file structure answer problem 7 through 13. 7. Identify and discuss the serious data redundancy problems exhibited by this file structure. 8. How many different data sources are likely to be used by the file you examined in problem 7? 9. Based on your findings in problem 7 and 8, how would a relational database environment help eliminate the data redundancy problems? 10. Given your answer to problem 9, how many tables would you use to substantially eliminate the data redundancy problems...
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...Comparison of Traditional File-Based Approach and Database Approach At the beginning, you should understand the rationale of replacing the traditional file-based system with the database system. File-based System File-based systems were an early attempt to computerize the manual filing system. File-based system is a collection of application programs that perform services for the end-users. Each program defines and manages its data. However, five types of problem are occurred in using the file-based approach: Separation and isolation of data When data is isolated in separate files, it is more difficult for us to access data that should be available. The application programmer is required to synchronize the processing of two or more files to ensure the correct data is extracted. Duplication of data When employing the decentralized file-based approach, the uncontrolled duplication of data is occurred. Uncontrolled duplication of data is undesirable because: i. Duplication is wasteful ii. Duplication can lead to loss of data integrity Data dependence Using file-based system, the physical structure and storage of the data files and records are defined in the application program code. This characteristic is known as program-data dependence. Making changes to an existing structure are rather difficult and will lead to a modification of program. Such maintenance activities are time-consuming and subject to error. Incompatible file formats ...
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...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 streaming •...
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...REVIEW QUESTIONS CHAPTER 1 DATABASE SYSTEMS (LAB ASSIGNMENT 1) 1) Discuss each of the following terms: * Data Data is information that has been translated into a form that is more convenient to move or process. Data is a raw fact or unprocessed information * Field Auto-increment allows a unique number to be generated when a new record is inserted into a table. * Record A record is for the purpose of future reference. A record is made in the form of data A table in database contained from rows called record Record is when related data is being processed, filed and kept, that is a record * File functions allow you to access and manipulate the filesystem 2) What is a DBMS, and what are its functions? Database Management System, is a software tool that makes it possible to organize data in a database. 3) Explain the difference between data and information? Data is a building block, Information gives meaning and context. 4) What are the main components of a database system? Explain why database design is important? An Access database consists of several different components. Each component listed is called anobject. Tables, Queries, Forms, Reports, Pages, Macros, Modules. Database Design is the database structure that will be used as plan to store and manage data. The database management system (DBMS) is the software used to implement a database design. 5) What is the role of a DBMS, and what are its advantages? What are...
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...AC571_relational_database_005-019 Male Page 1 of 5 AC571_relational_database_005 Welcome to this refresher on relational database concepts. Understanding relational database concepts is a key to mastering a key theme, REA modeling. As we progress through this refresher, please pay close attention to the objectives being covered as you see on the screen. The objectives are as follows: problems inherent in the flat file approach to data management that gave rise to the relational database concept, relationships among the defining elements of the relational database environment, stages in database design, entity identification, data modeling, constructing the physical database, and preparing user views, features of distributive databases and issues to consider in deciding on a particular database configuration. These objectives will serve as the foundation for understanding relational database concepts and REA modeling. AC571_relational_database_006 Before we can get into the heart of relational database concepts one must understand the differences between two common database environments, flat file and relational databases. As you know, computer systems process data. This processing involves two key components, data and instructions, or programs. This occurs no matter what database environment you have. In order to process the data you need an interface. Conceptually there are two methods for designing the interface between program instructions and data. File oriented processing...
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...1. a) What is a database? A database is an organized collection of related data. b) How does an RDBMS store data? An RDBMS stores related data in tables. 2. What is one benefit of dividing data into tables? Dividing data into tables eliminates unnecessary data duplication, or data redundancy. 3. a) What is a database schema? A database schema is a description of the data and the organization of the data into tables in a relational database. b) Explain the considerations for dividing data into related groups. Considerations for dividing data into related groups includes grouping information so that there is little or no data redundancy. However, each table must have data related to at least one other table, which will require data duplication. This is not considered data redundancy. A table with no relationship to any another table does not belong in the database. 4. a) What is a field? A column in a table. Used to store data. b) Explain why a field that stores more than one piece of data is considered poor design. A field that stores more than one piece of data limits the sorting and searching capabilities of the database. 5. List four guidelines to follow when choosing field names. 1. Make field names unique. 2. Choose...
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...a) What is a database? A database is an organized collection of related data. b) How does an RDBMS store data? An RDBMS stores related data in tables. 2. What is one benefit of dividing data into tables? Dividing data into tables eliminates unnecessary data duplication, or data redundancy. 3. a) What is a database schema? A database schema is a description of the data and the organization of the data into tables in a relational database. b) Explain the considerations for dividing data into related groups. Considerations for dividing data into related groups includes grouping information so that there is little or no data redundancy. However, each table must have data related to at least one other table, which will require data duplication. This is not considered data redundancy. A table with no relationship to any another table does not belong in the database. 4. a) What is a field? A column in a table. Used to store data. b) Explain why a field that stores more than one piece of data is considered poor design. A field that stores more than one piece of data limits the sorting and searching capabilities of the database. 5. List four guidelines to follow when choosing field names. 1. Make field names unique. 2. Choose the shortest possible...
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...began as a single tractor-trailer company. This company is growing is size and acquiring rapid business growth. At present time, the company owns 800 road tractors, 2,100 45' trailers, and 260 “roll A on/roll-off" units. The Huffman Trucking provides logistics services to U.S. Government as well as to the private companies. (Huffman Trucking, 2012). Learning team D’s project is to develop database design documentation for Huffman Trucking for their fleet truck maintenance. Huffman trucking interviewed members of their staff from different departments and proposed entities and attributes for their database. Entities proposed are numerous: Parts Inventory Purchases, Parts Inventory Issues, Parts Catalogue, Vendors, Parts Purchasing History, Vehicle Maintenance, Tire Maintenance, Maintenance Descriptions, Vehicle Types, Vehicles, and Maintenance Work Order. (Apollo Group, 2007). The expected end result from Huffman trucking is documentation showing entity relationship diagrams with referential integrity, data entry forms, SQL table join query code with results, and a normalized database that observes the business rules proposed by Huffman Trucking. Stages of Development In the first stage of development, we took the list of entities and their attributes proposed by our client and acquainted ourselves with their business and processes. The entities proposed by Huffman Trucking were numerous: Parts Inventory Purchases, Parts Inventory Issues, Parts Catalogue, Vendors, Parts...
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...definition Term: Database management. Tejaswy. Polasani 901767790 ENG 160-104 DT: 09-26-2014 Data is a vital part in any organization. It has to be stored, organized, manipulated and protected. Database management system stores the data in such a way that inputting, outputting, storing, retrieving and managing information becomes easier .It is a software that provides interface between users and databases and responsible for maintaining the integrity and security of stored data, and for recovering information if the system fails. The four components of dbms are: Users, Database, Database application and Database Management Systems. Users: they use forms to read, enter, delete and query data. The users include administrators, end users and designers. Administrators: They look after the maintenance of the database which include system license and other things related to maintenance. End users: They are the business analysts. Designers: They design the database. Database systems: create and process forms, queries, control data base applications. Database: It is used to create, monitor and access the database. Dbms performs the following functions....
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...Chapter 1 Database Systems Discussion Focus How often have your students heard that “you have only one chance to make a good first impression?” That’s why it’s so important to sell the importance of databases and the desirability of good database design during the first class session. Start by showing your students that they interact with databases on a daily basis. For example, how many of them have bought anything using a credit card during the past day, week, month, or year? None of those transactions would be possible without a database. How many have shipped a document or a package via an overnight service or via certified or registered mail? How many have checked course catalogs and class schedules online? And surely all of your students registered for your class? Did anybody use a web search engine to look for – and find – information about almost anything? This point is easy to make: Databases are important because we depend on their existence to perform countless transactions and to provide information. If you are teaching in a classroom equipped with computers, give some “live” performances. For example, you can use the web to look up a few insurance quotes or compare car prices and models. Incidentally, this is a good place to make the very important distinction between data and information. In short, spend some time discussing the points made in Section 1.1, “Data vs. Information.” After demonstrating that modern daily life is almost inconceivable...
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...5.1 relational algebra 6 5.1.1 select 7 5.1.2 project 8 5.1.3 join 8 5.1.3.1 equa-join 8 5.1.3.2 theta-join 9 5.1.3.3 natural join 9 5.1.3.4 outer join 10 5.1.4 intersect 11 5.1.5 union 11 5.1.6 difference 11 5.1.7 Cartesian product 12 5.1.8 division 12 5.2 relational calculus 13 6 Meta Data Components 13 6.1 data dictionary 13 6.2 system catalog 13 6.2.1 synonym 14 6.2.2 homonym 14 7 Relationship Types 14 7.1 1:1 14 7.2 1:N 15 7.3 M:N 16 7.3.1 intersection table 16 7.3.2 dummy table 17 8 Data Redundancy in Relational Model 17 9 Indexes 17 9.1 pointer 18 9.2 unique index 18 9.3 non-unique index 18 1 Objectives • The relational database model takes a logical view of data. • The relational model's basic components are entities, attributes, and relationships among entities. • Entities and their attributes are organized into tables. • Know relational database operators, the data dictionary, the system catalog. • How data redundancy is handled in the relational model. • Why is indexing important? 2 Logical View of Data Relational model • Enables us to view data logically rather than physically • Reminds us of simpler...
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...1. Besides redundancy, what other problems are associated with the nondatabase approach to processing data? Another problem with the nondatabase approach is accessing related data. In order to access data that is related to one another, you would have to open multiple spreadsheets, nondatabase systems also have way less security features than a database system. 2. What is a relationship? A one to many relationship? A relationship is an association between entities. A one-to-many relationship is a relationship where one entity is related to a group of entities, and everything in that group of entities is related to the first entity but they are not related to each other. 3. How do you create a one-to-many relationship in a database system? To create a one-to-many relationship in a database you will first need to create an entity, this entity should have something in common with the entities that it is related to, meaning they need to have at least one attribute in common. 4. What is a DBMS? DBMS stands for database management system, which is a program, or collection of programs, through which users interact with a database. 5. What is a form? A form is screen object used to maintain, view, and print data from a database. 6. What is meant by the sharing of data? Sharing data allows many different users to have access to the same data, if one user changes or updates that data the changes will be visible to all users. 7. How does consistency result from...
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...Michael Cooper 9/11/15 Role in the Database Environment A database management system is the software system that allows users to define, create and maintain a database and provides controlled access to the data. A Database Management System (DBMS) is basically a collection of programs that enables users to store, modify, and extract information from a database as per the requirements. DBMS is an intermediate layer between programs and the data. Programs access the DBMS, which then accesses the data. There are different types of DBMS ranging from small systems that run on personal computers to huge systems that run on mainframes. There are a lot of database software manufacturers out there and a wide range of prices, sizes, speeds and functionalities. At the lower end of the scale are personal database software products like Microsoft Access, which is designed to be used by individuals or small companies relatively little data. User friendliness and ease of use are the priority rather than speed and scalability (in other words, it works well when you have 100 records but not when you have 100,000). At the higher end are full-fledged enterprise solutions, such as Oracle Enterprise Edition. These database software products can handle millions of data entries and are fast and efficient. They have ·many optimization and performance tools and generally require a Database Administrator (DBA) to look after them. Products in this range can also be very expensive. In file system, each...
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...DCS5078 DATABASE SYSTEMS TUTORIAL 1 CHAPTER 1 1. Discuss each of the following terms: a. Data b. Field c. Record d. File 2. What is data redundancy, and which characteristics of the file system can lead to it? 3. What is a DBMS, and what are its functions? 4. What is a business rule, and what is its purpose in data modeling? Given the file structure shown in Figure T1.1, answer Problems 5 - 8. FIGURE T1.1 The File Structure for Problems 5-8 5. How many records does the file contain, and how many fields are there per record? 6. What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure? 7. If you wanted to produce a listing of the file contents by last name, area code, city, state, or zip code, how would you alter the file structure? 8. What data redundancies do you detect, and how could these redundancies lead to anomalies? FIGURE T1.5 The File Structure for Problems 9-11 9. Identify and discuss the serious data redundancy problems exhibited by the file structure shown in Figure T1.5. CDP OCT 2014/2015 1 DCS5078 DATABASE SYSTEMS TUTORIAL 1 10. Identify the different data sources in the file you examined in Problem 9. 11. Given your answer to Problem 10, what new files should you create to help eliminate the data redundancies found in the file shown in Figure T1.5? Use the contents of Figure T1.11 to work problems 12. FIGURE T1.11 Linking Relational...
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