d) The actual movement of a body is collected as digital data, and on the basis of such data, multiple images with realistic movement are created. Q26.Which of the following is an appropriate explanation concerning the data structure in a relational database? a) Data and methods are unified (i.e., encapsulated) and stored. b) Data is represented with one or more two-dimensional tables. c) Parent records and child records are linked with a pointer. d) Tags are used to represent data structure and meaning. Q27. In a relational database, there are two conditions that must be met as a primary key constraint. One condition is that there are no duplicate key values. Which of the following is another condition? a) The primary key must be composed of only one column. b) The primary key must be defined as the first column of a table. c) The primary key value must match the candidate key of another table. d) The primary key value must not be null. –13–
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Q28.In order to find all rows from the “Books” table that include “UNIX” in the title, the SQL statement is used as shown below. Which of the following is an appropriate character string that is specified in blank A? Here, the title is stored in the “Title” column of the “Books” table. SELECT * FROM Books WHERE Title LIKE'A 'a) %UNIXb) %UNIX%c) UNIXd) UNIX%Q29.Which of the following is the relational operation that corresponds to the manipulation of the SQL statement for Table R shown below? R A1 A2 A3 A4 A5 [SQL statement] SELECT A1, A3, A5 FROM R a) Difference b) Join c) Projection d) Selection –14–