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Total 131 questions
Which mechanism provides database users with controlled access to the database through the use of virtual tables?
- A. View
- B. Data dictionary
- C. Database control language
- D. Database management system
Answer : A
Which subset of Structured Query Language (SQL) is used to create and name database entities?
- A. Data Control Language
- B. Database Entity Language
- C. Data Definition Language
- D. Data Manipulation Language
Answer : C
Which subset of Structured Query Language (SQL) is used to limit access to a database or its data?
- A. Data Definition Language
- B. Data Control Language
- C. Data Entity Language
- D. Data Manipulation Language
Answer : B
Which of the following ACID properties requires that a transaction be executed in its entirety or not all?
- A. Durability
- B. Consistency
- C. Isolation
- D. Atomicity
Answer : D
Consider the entity-relation (ER) diagram shown in the exhibit. When the logical database design phase is completed, which of the following is a valid DBDL description of the base relations for the ER diagram?
- A. STUDENT( Student_Number: integer NOT NULL Name: variable length character string length 20 NOT NULL) Primary Key Student_Number CLASS( Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num
- B. STUDENT( Student_Number: integer NOT NULL Name: variable length character string length 20 NOT NULL) Primary Key Student_Number CLASS( Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num Foreign Key Class_Num References STUDENT
- C. STUDENT( Student_Number: integer NOT NULL Name: variable length character string length 20 NOT NULL) Primary Key Student_Number STU_CLASS( Student_Number: integer NOT NULL Class_Num: integer NOT NULL) Primary Key Student_Number CLASS( Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num
- D. STUDENT( Student_Number: integer NOT NULL Name: variable length character string length 20 NOT NULL) Primary Key Student_Number STU_CLASS( Student_Number: integer NOT NULL Class_Num: integer NOT NULL) Primary Key Student_Number CLASS( Class_Num: integer NOT NULL Class_Name: integer NOT NULL) Primary Key Class_Num
Answer : D
Which pair of relational algebraic operations requires union compatibility?
- A. Projection and Cartesian product
- B. Selection and projection
- C. Intersection and difference
- D. Cartesian product and intersection
Answer : C
Your enterprise is developing a database system that will contain highly sensitive data.
Security of the data will take priority over database processing speed. Which database protection technique should be employed?
- A. Backups
- B. User views
- C. Encryption
- D. Integrity controls
Answer : C
In which situation would the DBMS use a serial schedule to execute the transactions?
- A. Concurrent transactions read data from the same data structure.
- B. Concurrent transactions write data to different data structures.
- C. Concurrent transactions read or write the same data structure.
- D. Concurrent transactions read or write from different data structures.
Answer : C
A theta-join can be viewed as:
- A. the intersection of two relations.
- B. a Cartesian product of two relations.
- C. a restricted Cartesian product of two relations.
- D. the Cartesian product of two union-compatible relations.
Answer : C
Which of the following best describes the ON DELETE CASCADE referential integrity constraint?
- A. If a parent key is deleted, any child keys referenced by the parent key are automatically deleted.
- B. If any child key references a parent key, the record containing the parent key cannot be deleted.
- C. If a parent key is deleted, all child keys are automatically set to a specified value.
- D. If a parent key is deleted, no test is made for referential integrity.
Answer : A
Which of the following definitions best describes an entity?
- A. A single relation
- B. Data about data
- C. Data stored in a table column
- D. An item about which information is stored
Answer : D
What is the highest normal form of the relation(s) shown in the exhibit?
- A. Third normal form
- B. Second normal form
- C. Boyce-Codd normal form
- D. First normal form
Answer : D
Which term describes the management of simultaneous transactions to prevent conflicts?
- A. Parallelism
- B. Serialization
- C. Database control
- D. Concurrency control
Answer : D
Consider the relation shown in the exhibit. Which of the following SQL statements would properly add information for a new employee?
- A. INSERT INTO Employee VALUES(0005, Tim, Bogart, 03-15-77);
- B. INSERT INTO Employee(Emp_ID, First_Name, Last_Name, Birth_Date) VALUES(0004, Tim, Bogart, 03-15-77);
- C. INSERT INTO Employee(Emp_ID, First_Name, Last_Name, Birth_Date) VALUES(0005, Tim, Bogart, 03-05-77);
- D. INSERT INTO Employee(Emp_ID, First_Name, Last_Name, Birth_Date) VALUES(0005, Tim, Bogart, 03-05-77);
Answer : D