key DBI202

A ____ is a relation name, together with the attributes of that relation. a. schema b. database c. database instance d. schema instance

A

A class in UML is similar to........... a. An entity set in E/R model b. An attribute in E/R model c. A Relationship in E/R model d. None of the others

A

A database of _____ data model is a collection of nodes, each node is either a leaf or interior a. semi-structured b. relational c. network d. object-relational

A

Foreign key constraints are created by using "_____" keyword to refer to the primary key of another table a. REFERENCES b. POINT TO c. REFER d. None of the others

A

How to eliminate anomalies when we design a database? a. We should decompose relation to eliminate anomalies b. We should join relations to eliminate anomalies c. We should union relations to eliminate anomalies d. None of the others

A

Schema-altering commands are known as _________ commands. a. Data Definition Language b. Data Manipulation Language c. Data Controlling Language d. None of the others

A

Suppose R is a relation with attributes A1, A2, A3, A4. The only key of R is {A1, A2}. So, how many super-keys do R have? a. 4 b. 8 c. 12 d. 16

A

The benefits of stored procedures are: (a)They improve the security by letting the admin to LIMIT the access rights of users (b) They can save a lot of storage space (c) They can be reused many times (d) They can store a part of the database in order to retrieve the data more quickly a. (a) and (c) are true b. (a) and (b) are true c. (a) and (d) are true d. (b) and (d) are true

A

Three basic types of database integrity constraints are: (a)Entity integrity (b) Domain integrity (c) Referential integrity (d) Primary key integrity a. (a) and (b) and (c) are true b. (a) and (b) and (d) are true c. (a) and (c) and (d) are true d. (b) and (c) and (d) are true

A

Three properties of a lock in DBMS are: a)Granularity: the size of the lock b) Granularity: the type of the lock c) Mode: the type of the lock d) Duration: the time in seconds that the DBMS waits for a lock to be released a. (a) and (c) and (d) are true b. (a) and (b) and (d) are true c. (b) and (c) and (d) are true d. (a) and (b) and (c) are true

A

What is "de-normalization"? a. De-normalization means allowing redundancy in a table b. De-normalization means allowing duplicate columns appeared in a table c. De-normalization means allowing a table to have more than 3 columns d. De-normalization means allowing a table to have more than 1024 columns

A

What is difference between PRIMARY KEY and UNIQUE KEY ? a. A table can have more than one UNIQUE KEY constraint but only one PRIMARY KEY b. A table can have more than one PRIMARY KEY constraint but only one UNIQUE KEY c. UNIQUE KEY and PRIMARY KEY are the same d. None of the others

A

What is the difference between the 2NF and the 3NF? a. 2NF deals with partial functional dependency, while 3NF deals with transitive functional dependency b. 2NF deals with transitive functional dependency, while 3NF deals with partial functional dependency

A

What is the hierarchical data model? a. A hierarchical data model is a data model in which the data is organized into a tree-like structure b. A hierarchical data model is a data model in which the data is organized into a table-like structure c. A hierarchical data model is a data model in which the data is organized into a graph-like structure d. None of the others

A

Which SQL keyword is used to sort the result-set? a. ORDER BY b. SORT BY c. ORDER d. SORT

A

Which statement is used to remove a relation named R? a. DROP TABLE R; b. REMOVE TABLE R; c. DELETE TABLE R; d. TRUNCATE TABLE R;

A

A/An _____ is a data structure that makes it efficient to find those tuples that have a fixed value for an attribute a. Trigger b. Index c. stored-procedure d. View

B

Choose the most correct statement. a. Database is created and maintained by a DMBS b. All of the others c. Database is a collection of data that is managed by a DBMS d. Database is a collection of information that exists over a long period of time

B

The ER Diagram uses three principle element types: a. Entity sets, Attributes and Constraints b. Entity sets, Attributes, and Relationships c. Attributes, Constraints, and Relationships d. Entity sets, Constraints, and Relationships

B

The most useful index on a relation is an index on its key. This is because: a. The index on non key attribute(s) runs slower b. The search operation based on the primary key is commonly used. c. The index on non key attribute(s) makes update operations to the relation more complex and time-consuming d. All of the others

B

What is another term for a row in a relational table? a. Attribute b. Tuple c. Field d. Relation

B

Which of following is never used as a data model? a. Hierarchical data model b. None of the others c. Graph-based data model d. Tree-based data model e. Relational data model

B

Which of the following statements is correct? a. All relations in 3NF are also in BCNF b. For any relation schema, there is a dependency-preserving decomposition into 3NF c. All relations in 2NF are also in BCNF

B

Which one of the following is NOT a DML command? a. DELETE b. ALTER TABLE c. INSERT d. UPDATE

B

___ allow the database application to find data fast, without reading the whole table a. Views b. Indexes c. Triggers d. Store-procedures

B

A ___ is a notation for describing the structure of the data in a database, along with the constraints on that data a. data operation b. database management system c. data model d. data manipulation

C

A ____ is a logically coherent collection of data with some inherent meaning, representing some aspect of real world and being designed, built and populated with data for a specific purpose a. Schema b. Database Instance c. Database d. Schema Instance

C

A ____ is a powerful tool for creating and managing large amounts of data efficiently and allowing it to persist over long periods of time, safely a. Excel b. Database c. DBMS d. None of the others

C

A _____ is a language for defining data structures a. DCL b. DML c. DDL d. None of the others

C

A(an) _____ asserts that a value appearing in one relation must also appear in the primary-key component(s) of another relation a. Unique key constraint b. Primary key constraint c. Foreign key constraint d. Candidate key constraint

C

How many JOIN conditions are necessary to combine five tables based on common attributes? a. 1 b. 2 c. 4 d. 3

C

In SQL , the command/statement that let you add an attribute to a relation schema is ....... a. Insert b. Update c. Alter d. None of the others

C

The binary relationship between classes in UML is called ... a. Aggregation b. Composition c. Association d. Relation

C

To update a relation's schema, which one of the following statements can be used? a. ALTER TABLE b. SELECT c. INSERT d. UPDATE

C

What operator tests column for the absence of data? a. IS BLANK operator b. IS ZERO operator c. IS NULL operator d. ISNULL operator

C

A ____ table is a table that is embedded within another table a. Child b. Primitive c. Parent d. Nested

D

An association class in UML is similar to ______ in the ER model a. entity sets b. Attributes c. Entities d. attributes on a relationship

D

Choose the correct statement. a. You can remove a trigger by dropping it or by dropping the trigger table. b. The syntax to remove a trigger is: DROP TRIGGER <trigger_name> c. Use ALTER TRIGGER to change the definition of a trigger d. All of the others.

D

Consider the following statement: "Entity Sets and their attributes should reflect the reality" That above statement describes which principle? a. Avoid Redundancy Principle b. Simplicity Count Principle c. Limit the use of weak entity sets principle d. Faithfulness principle

D

Given a relation R(A,B,C,D). Which of the followings is trivial? a. A->AB b. A->->AB c. A->BCD d. A->->BCD

D

The key for a weak entity set E is ......... a. Zero or more attributes of E b. The set of attributes of supporting relationships for E c. The set of attributes of supporting entity sets d. Zero or more attributes of E and key attributes from supporting entity sets

D

Which of the following statements is the most correct? a. Using Stored procedures reduces network traffic b. Using Stored procedures improves security c. Using Stored procedures improves performance d. All of the others

D

Which of the following statements is true? a. BCNF condition guarantees the non existence of the anomalies. b. In BCNF condition, the left side of every non trivial FD must be a super key. c. Any two-attribute relation is in BCNF. d. All of the others.

D

3NF concept is related to (choose 1 answer only): a. Atomic definition b. Full dependency definition c. Transitive dependency definition d. Super Key definition e. All of the others

E

Choose the most correct statement about PRIMARY KEY: a. The PRIMARY KEY constraint uniquely identifies each record in a database table b. Primary keys must contain unique values c. A primary key column cannot contain NULL values d. Each table should have a primary key, and each table can have only ONE primary key e. All of the others

E

In _____ Data Model, the data and relations between them are organized in tables a. Tree-based b. Network c. Flat-file d. Object-oriented e. Relational

E