1. What is a subquery and what are its basic characteristics? A subquery is a query (expressed as a SELECT statement) that is located inside another query. The first SQL statement is known as the outer query, the second is known as the inner query or subquery. The inner query or subquery is normally executed first. The output of the inner query is used as the input for the outer query. A subquery is normally expressed inside parenthesis and can return zero, one, or more rows and each row can have
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Hello sirs, my name is Percy A. Grisby II, I am forwarding this correspondence to give you options pertaining to your database management system or DBMS. One of these options is to install an Entity Relationship Model or E-R model DBMS, the reason I am suggesting an E-R model is there are a number of advantages to installing and managing this type of DBMS in your company. I will provide you with information on the advantages of them in this proposal. In this fast paced and competitive business world
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unique name and table duplication is not allowed. Example of database: Oracle 10g, MySQL, SQL Server, IBM DB2 etc. DBMS terms refer to the database management system. A database management system (DBMS) is a collection of software application package with some computer programs that are used to store, create, fetch, modify and extract the information from the database. Each DBMS system has some set of rules and pre-defined paradigm on which each database is working. There are many different types
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unique name and table duplication is not allowed. Example of database: Oracle 10g, MySQL, SQL Server, IBM DB2 etc. DBMS terms refer to the database management system. A database management system (DBMS) is a collection of software application package with some computer programs that are used to store, create, fetch, modify and extract the information from the database. Each DBMS system has some set of rules and pre-defined paradigm on which each database is working. There are many different types
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Chapter 1 – Review Questions 1.1 What is the purpose of a database? - The purpose of a database is to help people keep track of things. 1.2 What is the most commonly used type of database? - The relational database is the most commonly used type of database. 1.7 Define the terms data and information. Explain how the two terms differ. - Data are facts and figures. Information is defined as knowledge derived from data, or as data presented in a meaningful context. Data is simply recorded in
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Chapter 7 Managing Data Resources True-False Questions | |The benefits of a DBMS are immediately tangible. | | | | | |Answer: False Difficulty: Easy Reference: p. 234 | |
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2. Convert: (d) 65 W into dB 10log(65) = 18.1291 dB (e) 10 dB into watts log^-1(10/10) = 10 W (f) – 5 dB into watts log^-1(-5/10) = 0.3162 W = 316.2 mW (g) –30 dBm into dBrn -30 + 90 = 60 dBrn (h) 15 dBrn into dBm AP3 = 30 AP3 = 30 AP2 = 25 AP2 = 25 AP1 = 10 AP1 = 10 2. A three-stage amplifier is shown with power gains. Calculate total power gain in decibels, and as a number. A_p(tot)_(dB) = (10)(25)(30) = 7500
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program-data independence. 1.5 Describe the five components of the DBMS environment and discuss how they relate to each other. (1) Hardware: The computer system(s) that the DBMS and the application programs run on. This can range from a single PC, to a single mainframe, to a network of computers. (2) Software: The DBMS software and the application programs, together with the operating system, including network software if the DBMS is being used over a network. (3) Data: The data acts as
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Chapter 1 Databases and Database Users Copyright © 2011 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Chapter 1 Outline Types of Databases and Database Applications Basic Definitions Typical DBMS Functionality Example of a Database (UNIVERSITY) Main Characteristics of the Database Approach Types of Database Users Advantages of Using the Database Approach When Not to Use Databases Copyright © 2011 Ramez Elmasri and Shamkant Navathe
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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
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