Which statement accurately distinguishes the roles of the wrapper and source description in a mediated schema? A The wrapper requests and parses data from the sources, while the source description converts data from the source schemas and values into the global representation. (B) The source description requests and parses data from the sources, while the wrapper converts data from the source schemas and values into the global representation. (C) The wrapper abstracts soyrce data, while the source description requests and parses data from the sources. (D) The source description abstracts source data, while the wrapper requests and parses data from the sources

Which statement accurately distinguishes the roles of the wrapper and source description in a mediated schema? A The wrapper requests and parses data from the sources, while the source description converts data from the source schemas and values into the global representation. (B) The source description requests and parses data from the sources, while the wrapper converts data from the source schemas and values into the global representation. (C) The wrapper abstracts soyrce data, while the source description requests and parses data from the sources. (D) The source description abstracts source data, while the wrapper requests and parses data from the sources

A Guide to SQL

9th Edition

ISBN:9781111527273

Author:Philip J. Pratt

Publisher:Philip J. Pratt

Chapter2: Database Design Fundamentals

Section: Chapter Questions

Problem 3TD

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Which statement accurately distinguishes the roles of the wrapper and source description in a mediated schema? A) The wrapper requests and parses data from the sources, while the source description converts data from the source schemas and values into the global representation. B) The source description requests and parses data from the sources, while the wrapper converts data from the source schemas and values into the global representation. C) The wrapper abstracts source data, whiye the source description requests and parses data from the sources. D) The source description abstracts source data, while the wrapper requests and parses data from the sources
Relations describe the intersection between two axes, x and y. For example, a table (tuple) found in a database contains columns (attributes) and rows (records or observations). Database and Geospatial Mapping Application developers rely on tables and cartesian coordinate systems to adhere to the rules of relational database theory so that integrity in the location is preserved. Tables should only contain records that relate to the columns found in that table and the data domain determines what records should be stored in a given table. Database administrators can check for integrity in relationships within and between tables using structured query language (SQL). What other computer-science or IT jobs rely on relations?
Design an ER schema for keeping track of information about votes taken in the U.S. House of Representatives during the current two-year congressional session. The database needs to keep track of each U.S. STATE's Name (e.g., 'Texas', 'New York', 'California') and include the Region of the state (whose domain is {'Northeast', 'Midwest', 'Southeast', 'Southwest', 'West'}). Each CONGRESS_PERSON in the House of Representatives is described by his or her Name, plus the District represented, the Start_date when the congressperson was first elected, and the political Party to which he or she belongs (whose domain is {'Republican', 'Democrat', 'Independent', 'Other'}). The database keeps track of each BILL (i.e., proposed law), including the Bill_name, the Date_of_vote on the bill, whether the bill Passed_or_failed (whose domain is {'Yes', 'No'}), and the Sponsor (the congressperson(s) who sponsored that is, proposed the bill). The database also keeps track of how each congressperson voted on…
Design an ER schema for keeping track of information about votes taken in the U.S. House of Representatives during the current two-year congressional session. The database needs to keep track of each U.S. STATE’s Name (e.g., ‘Texas’, ‘New York’, ‘California’) and include the Region of the state (whose domain is {‘Northeast’, ‘Midwest’, ‘Southeast’, ‘Southwest’, ‘West’}). Each CONGRESS_PERSON in the House of Representatives is described by his or her Name, plus the District represented, the Start_date when the congressperson was first elected, and the political Party to which he or she belongs (whose domain is {‘Republican’, ‘Democrat’, ‘Independent’,‘Other’}). The database keeps track of each BILL (i.e., proposed law), including the Bill_name, the Date_of_vote on the bill, whether the bill Passed_or_failed (whose domain is {‘Yes’, ‘No’}), and the Sponsor (the congressperson(s) who sponsored—that is, proposed—the bill). The database also keeps track of how each congressperson voted on…
Develop an EER model for the following situation using the traditional EER notation, the Visio notation, or the subtypes inside supertypes notation, as specified by your instructor: An international school of technology has hired you to create a database management system to assist in scheduling classes. After several interviews with the president, you have come up with the following list of entities, attributes, and initial business rules: • Room is identified by Building ID and Room No and also has a Capacity. A room can be either a lab or a classroom. If it is a classroom, it has an additional attribute called Board Type. • Media is identified by MType ID and has attributes of Media Type and Type Description. Note: Here we are tracking type of media (such as a VCR, projector, etc.), not the individual piece of equipment. Tracking of equipment is outside the scope of this project. • Computer is identified by CType ID and has attributes Computer Type, Type Description,…
Part 3 5. Database design often involves decisions about the storage of attributes. For example a Telephone Number can be stored as a one attribute or split into three attributes (one for each of the three hyphen-delineated groups of numbers in a Telephone Number (XXX)-XXX-XXXX, I.e (123)-456-7890). However, Telephone Number is usually stored in one attribute. The decision is usually based on how the database will be used. This exercise asks you to think about specific situations where dividing the Telephone Number is useful. List and describe the different situations, give examples.
The following are the objectives for the design of the logical schema:
1. Draw an E/R diagram for a University database. This database should contain information about the university's students, departments, professors, teaching assistants (also students of the university), courses offered by a department, which students are enrolled in what courses, which professors are teaching which courses, student letter grades. You may include any other information deemed appropriate. • Some restrictions apply as listed below| 1. A Professor only works in at most one department. 2. Students and professors have been assigned unique email id's 3. A course is only taught by one professor and offered by one department. 4. A course is uniquely identified by the course number, section number and semester. Example: CSCE520-001 Spring21 5. A course has at most one TA.
142. The objects in database description is called a. concept construct b. entity construct c. schema construct d. attribution construct
A three-schema design has three levels, and at each level, requests are turned into results.
167. In Three-Schema Architecture, the schema which gives details about data types, constraints and entities is classified as a. internal schema b. external schema c. logical schema d. conceptual schema
In a three-schema design, requests are translated into results at each of the three tiers.