Database Key
(FALSE AND NULL) return: A. NULL B. TRUE C. FALSE D. None of the others
a
(TRUE AND NULL) returns: ??? a. NULL b. TRUE c. FALSE d. None of the others
a
A relation is a set of tuples [A] True [B] False
a
A. (2,3) appears twice in the result. B. (2,3) appears three times in the result. C. (3,3) appears once in the result. D. (2,2) appears once in the result.
a
Choose a wrong answer. [A] Relational algebra can express recursion. [B] Basic relational algebra can be expressed in Datalog rule(s). IC] Single Datalog rule can be expressed in relational algebra. [D] Datalog does not support bag operations.
a
Choose an incorrect statement [A] None of the others [B] Database is created and maintained by a DMBS IC] Database is a collection of information that exists over a long opened of time [D] Database is a collection of data that is managed by a DBMS
a
Choose the correct statement A.Except for COUNT, aggregate functions ignore null values B.Except for SUM, aggregate functions ignore null values C.Except for AVG, aggregate functions ignore null values D.Except for MIN, aggregate functions ignore null values E.Except for MAX, aggregate functions ignore null values
a
Choose the right statement below to declare zero or one occurrence of an Element in DTD. [A] <"ELEMENT element-name (child-name?)> [B] <IELEMENT element-name (child-name+)> [C] <'ELEMENT element-name (child-name*)> [D] <IELEMENT element-name (child-name)>
a
Database integrity ensures that: a. data entered into the database is accurate, valid, and consistent b. data entered into the database is accurate, and consistent c. data entered into the database is valid, and consistent d. data entered into the database is accurate, and valid
a
Give the relation Employee(SSN,FNAME,LNAME,SALARY).Select the right query below to find the employee(s) who has the lowest salary in the company A. SELECT LNAME,FNAME,SALARY FROM Employee WHERE SALARY IN ( SELECT MIN(SALARY) FROM Employee) B. SELECT LNAME,FNAME,SALARY FROM Employee WHERE SALARY >=ALL( SELECT MIN(SALARY) FROM Employee) C. SELECT LNAME,FNAME,SALARY FROM Employee WHERE SALARY < MAX ( SELECT MIN(SALARY) FROM Employee) D. None of the others
a
Given the relation Employee(SSN. FNAME. LNAME. SALARY). Select the right query below to find the employee(s) who has the lowest salary in the company [A] SELECT LNAME. FNAME. SALARY FROM Employee WHERE SALARY IN (SELECT MIN(SALARY) FROM Employee) [B] SELECT LNAME. FNAME. SALARY FROM Employee WHERE SALARY >= ALL (SELECT SALARY FROM Employee) [C] SELECT LNAME. FNAME. SALARY FROM Employee WHERE SALARY < MAX (SELECT SALARY FROM Employee) [D] None of the others
a
In DTD. the main difference between PCDATA and CDATA is [A] PCDATA is text that will be parsed by a parser and tags inside the text will be treated as markup and entities will be expanded CDATA is text that will NOT be parsed by a parser and tags inside the text wil NOT be treated as markup and entities will not be expanded. [B] All of the others. [C] CDATA is used to assert something about the allowable content of elements where as PCDATA is used as a common type for attribute [D] There's no difference between PCDATA and CDATA.
a
In SQL language, the command/statement that let you add an attribute to a relation is_ [A] Alter [B] None of the others [C] Insert [D] Update
a
In UML, a _____ between classes is called an association a.binary relationship b.multi-way relationship c.none of the others
a
In relational data model, a tuple is a record or a row [A] True [B] False
a
Often, a DBMS allows us to build a single index on ____ attribute(s) (choose the most correct answer) a. only one b. two c. three d. multiple
a
Pay attention into the following query: SELECT * FROM R WHERE A LIKE '%a%'; So, in the above case, the wildcard % represents what? a. % (percent sign) represents zero, one, or more character b. % (percent sign) represents exactly 1 character
a
QN=1 (6797) 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. DBMS b. Database c. Excel d. None of the others
a
QN=1 (6803) 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. Database b. Database Instance c. Schema d. Schema Instance
a
QN=11 (7966) 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
QN=12 (7962) What is a functional dependency? a. A functional dependency (A->B) occurs when the attribute A uniquely determines B b. A functional dependency (A->B) occurs when the attribute B uniquely determines A
a
QN=12 (7990) Consider the following functional dependencies a,b -> c,d e,g,h -> f,j a,c -> b,d p,q -> r,s e,f,g -> h,i s -> t f,g -> j q -> u g,h -> i Which of the following best describes the relation R(e,f,g,h,i,j)? a. R is in First Normal Form b. R is in Second Normal Form c. R is in Third Normal Form d. R is in Boyce Codd Normal Form
a
QN=13 (6815) Which is the subset of SQL commands used to manipulate Database structures, including tables? a. DDL (Data Definition Language) b. DML (Data Manipulation Language) c. DCL (Data Control Language) d. All of the others
a
QN=13 (7978) The relation R(ABCD) has following FDs: { A -> B ; B -> A ; A -> D ; D -> B } a. R is in 3NF b. R is not in 3NF c. R is not in 2NF d. None of the others
a
QN=14 (7970) What is a key attribute in a relation? a. A key attribute is an attribute that belongs to one of the keys of the relation b. A key attribute is an attribute that belongs to one of the super keys of the relation
a
QN=14 (7976) Given a R(A,B,C,D) with the following FDs: AB->D BC->A AD->B CD->B AD->C Choose a correct statement about R: a. The FD set of R is not canonical and R is in BCNF b. The FD set of R is canonical and R is not in BCNF c. The FD set of R is not canonical and R is not in BCNF
a
QN=15 (6823) "R(A,B,C,D)" is an example of: a. A schema b. A relation c. A relation instance d. A schema instance
a
QN=15 (7984) Which of the following relations is in Boyce-Codd Normal Form (BCNF)? a. R(ABCD) with FD's: BD -> C ; AB -> D ; AC -> B ; BD -> A b. R(ABCD) with FD's: BC -> A ; AD -> C ; CD -> B ; BD -> C c. R(ABCD) with FD's: A -> C ; B -> A ; A -> D ; AD -> C d. R(ABCD) with FD's: A -> D ; C -> A ; D -> B ; AC -> B
a
QN=10 (7972) Let R(ABCD) be a relation with functional dependencies {A -> B, C -> B, B -> D} What is the key for R (choose one) a. AB b. AC c. AD d. BD
b
QN=15 (7999) 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
QN=16 (6813) Which statement is used to remove a column named D from the relation R? a. ALTER TABLE R DROP COLUMN D; b. ALTER TABLE R DROP COLUMN D [DataType]; c. ALTER TABLE R DELETE COLUMN D; d. ALTER TABLE R DELETE COLUMN D [DataType];
a
QN=16 (7993) 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
QN=17 (7979) The relation R(ABCD) has following FDs: {ACD -> B ; AC -> D ; D -> C ; AC -> B} Choose the correct statement about R: a. R is in 3NF b. R is in 2NF only, not higher c. R is in 1NF only, not higher d. None of the others
a
QN=18 (8537) What is a "join"? a. 'join' used to connect two or more tables logically with or without common field(s) b. 'join' used to connect two or more tables logically with common field(s) c. 'join' used to connect two or more tables logically without common field(s) d. 'join' used to connect two or more tables logically with aliases
a
QN=19 (6822) Which statement is used to add a column named D into the relation R? a. ALTER TABLE R ADD D [DataType]; b. ALTER TABLE R ADD ATTRIBUTE D [DataType]; c. ALTER TABLE R ADD PROPERTY D [DataType];
a
QN=19 (8019) 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
QN=2 (6808) What is a database? a. A database is a collection of information that is organized so that it can easily be accessed, managed, and updated b. A database is a collection of data files c. A database is a collection of records d. A database is a collection of tuples
a
QN=20 (8013) A(n) _____ provides a means to analyze business requirements so as to standardize organizational vocabulary, enforce business rules, and ensure adequate data quality a. Entity Relationship Diagram b. Relation Schema Design c. All of the others d. None of the others
a
QN=21 (7995) 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
QN=21 (8032) An association class in UML is similar to ______ in the ER model a. attributes on a relationship b. Attributes c. Entities d. entity sets
a
QN=22 (7994) What is the goal of decomposition when designing a database? a. The goal of decomposition is to replace a relation by several relations that do not exhibit anomalies b. The goal of decomposition is to increase the speed of the database c. The goal of decomposition is to increase the security of the database d. None of the others
a
QN=22 (8009) In UML, what is the difference between an aggregation and a composition? a. In composition, when the owning object is destroyed, so are the contained objects. In aggregation, this is not necessarily true. b. In aggregation, when the owning object is destroyed, so are the contained objects. In composition, this is not necessarily true. c. All of the others d. There is no difference between an aggregation and a composition
a
QN=23 (8222) Which of the following is NOT a standard aggregation operator? a. GROUP b. SUM c. COUNT d. AVG
a
QN=25 (8010) Look at the following statements: (a)We should pick the right kind of elements (b) When an entity has no non-primary key attribute, we should convert that entity to an attribute (c) Use weak entities when-ever possible (d) Always make redundancies a. (a) and (b) are correct b. (a) and (c) are correct c. (a) and (d) are correct d. (b) and (c) are correct
a
QN=25 (8236) Choose the correct statement: a. Aggregate functions perform a calculation on a set of values and return a single value b. Aggregate functions perform a calculation on a single value and return a single value c. Aggregate functions perform a calculation on a set of values and return a relation d. Aggregate functions perform a calculation on a set of values and return a row
a
QN=26 (8507) Suppose the relation S(B,C,D) has tuples: B C D ------------------------------------ a 4 6 c 6 8 c 5 5 e 9 9 F 10 10 c 7 9 Compute the result of the following query: SELECT SUM(D) FROM S WHERE D < 8 AND D > 5 Choose the row that appears in the computed result. a. 6 b. 7 c. 8 d. 9
a
QN=28 (8231) Consider the Datalog rule H(x,y) <- S(x, y) AND x > 2 AND y < 6. Relation S(x, y) has 3 tuples (2, 3), (3, 5), and (4, 6). What is about H? a. H has a tuple (3, 5) b. H has a tuple (2, 3) c. H has 2 tuples (2, 3) and (3, 5) d. H has 3 tuples (2, 3) and (3, 5) and (4, 6)
a
QN=29 (7967) A set of attributes forms a ____ for a relation if we do not allow 2-tuples in a relation instance to have the same values in all that attributes a. Key b. Foreign Key c. Index Key d. Trigger Key
a
QN=29 (8513) The table Arc(x,y) currently has the following tuples (note that there are duplicates): (1,2), (1,2), (2,3), (3,4), (3,4), (4,1), (4,1), (4,1), (4,2). Compute the result of the query: SELECT a1.x, a2.y, COUNT(*) FROM Arc a1, Arc a2 WHERE a1.y = a2.x GROUP BY a1.x, a2.y; Which of the following tuples is in the result? a. (3,1,2) b. (1,3,4) c. (2,4,6) d. (3,2,6)
a
QN=54 (9171) In PSM, the difference between a stored procedure and a function is that: a. A function has the return statement. b. We can declare local variables in a function. c. Loops are not allowed in a function. d. All of the others.
a
QN=3 (6800) 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
QN=30 (8232) Suppose that tuple t appears, respectively, x, y, and z times in the relations X, Y, and Z. Let t appear w times in the relation: X union (Y intersect Z). Which of the following inequalities is true ? a. w <= x+y b. w <= y+z c. w >= z d. w <= max(x,y)
a
QN=30 (8517) How we can understand about this statement: "All aggregate functions are deterministic"? a. This means aggregate functions return the same value any time they are called by using a specific set of input values b. This means aggregate functions return the different values each time they are called by using a specific set of input values c. This means aggregate functions return the same value any time they are called by using any set of input values d. None of the others
a
QN=33 (8522) The table Arc(x,y) currently has the following tuples (note there are duplicates): (See picture) Compute the result of the query: SELECT x, COUNT(y) FROM Arc GROUP BY x; Which of the following tuples is in the result? [file:8522.jpg] a. (4,4) b. (4,5) c. (4,6) d. (4,7) e. (4,8)
a
QN=34 (8539) For what values of x, y, and z, including NULL, does the Boolean expression x <= 4 OR NOT(y >= 2 AND z = 10) have the truth value FALSE? Identify one of those values from the list below a. x = 5, y = 3, z = 10 b. x = 3, y = 1, z = 10. c. x = NULL, y = 2, z = 10. d. x = NULL, y = 3, z = 10.
a
QN=36 (8542) What does NULL mean? a. The value NULL means UNKNOWN b. The value NULL means '' (empty string) c. The value NULL means ' ' (space character) d. The value NULL means ZERO
a
QN=38 (8557) Which SQL keyword is used to sort the result-set? a. ORDER BY b. SORT BY c. ORDER d. SORT
a
QN=39 (8531) Here are three relations, R(A,B), S(C,D). Their current values are: R A B ------------------- 1 4 2 5 3 6 4 7 S C D ------------------- 0 1 1 0 2 1 Compute the result of the query: SELECT A, B, C, D FROM R LEFT OUTER JOIN S ON R.A = S.C Identify, in the list below, the row that appears in the result. a. (4, 7, null, null) b. (4, 7, 0, 1) c. (4, 7, 1, 0) d. (4, 7, 2, 1)
a
QN=39 (8558) 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
QN=4 (6795) In _____ Data Model, the data and relations between them are organized in tables a. Relational b. Network c. Flat-file d. Object-oriented e. Tree-based
a
QN=4 (6817) A ____ is a relation name, together with the attributes of that relation. a. schema b. database c. database instance d. schema instance
a
QN=40 (8534) A tuple which fails to participate in a join is called: a. dangling tuple b. child tuple c. parent tuple d. neighbor tuple
a
QN=41 (8538) (TRUE OR NULL) return: a. TRUE b. FALSE c. NULL d. None of the others
a
QN=43 (8003) Look at the following statements: (a) For any relation schema, there is a dependency-preserving decomposition into 3NF (b) For any relation schema, there is not dependency-preserving decomposition into 3NF (c) For any relation schema, there is dependency-preserving decomposition into BCNF (d) For some relation schema, there is not dependency-preserving decomposition into BCNF a. (a) and (d) are true b. (a) and (b) are true c. (a) and (c) are true d. (b) and (d) are true
a
QN=43 (8554) For what values of x, y, and z, including NULL, does the Boolean expression x <= 100 AND NOT(y >= 15 OR z = 35) have the truth value UNKNOWN? Identify one of those values from the list below. a. x = NULL, y = 0, z = 4. b. x = -2, y = -2, z = -2. c. x = 3, y = 0, z = 7. d. x = 2, y = -1, z = 6.
a
QN=43 (8610) In order to modify or delete an existing constraint, it is necessary that: a. the constraint has a name b. the constraint has an ID c. the constraint has some attributes
a
QN=44 (8551) Choose one correct statement: a. No two null values are equal b. Two null values are equal c. Comparisons between two null values, or between a NULL and any other value, return FALSE
a
QN=45 (8006) What is "normalization"? a. Normalizing data means eliminating redundant information from a table and organizing the data so that future changes to the table are easier b. Normalizing data means minimizing columns from a table and organizing the data so that future changes to the table will be made more quickly c. Normalizing data means removing columns from a table and organizing the data so that future changes to the table will be made more quickly d. Normalizing data means adding more columns to a table and organizing the data so that future changes to the table will be made more quickly
a
QN=10 (6830) Which one of the following is NOT a DML command? a. DELETE b. ALTER TABLE c. INSERT d. UPDATE
b
QN=45 (8592) To create a DEFAULT constraint on the "City" column of the table PERSON which is already created, use the following SQL: a. ALTER TABLE Person ALTER COLUMN City SET DEFAULT 'SANDNES' b. ALTER TABLE Person EDIT COLUMN City SET DEFAULT 'SANDNES' c. ALTER TABLE Person UPDATE COLUMN City SET DEFAULT 'SANDNES' d. ALTER TABLE Person MODIFY COLUMN City SET DEFAULT 'SANDNES'
a
QN=46 (8582) 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
QN=47 (8578) What one is a wildcard used for pattern matching? a. "%" (for multi-character substitution) b. "?" (for single character substitution) c. "?" (for multi-character substitution)
a
QN=48 (8600) 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
QN=49 (8637) A/An _____ is a data structure that makes it efficient to find those tuples that have a fixed value for an attribute a. Index b. Trigger c. stored-procedure d. View
a
QN=5 (6824) A ___ is a notation for describing the structure of the data in a database, along with the constraints on that data a. data model b. database management system c. data operation d. data manipulation
a
QN=5 (6833) Why the intersection operator is not called a primitive relational algebra operator? a. Because the intersection operator can be expressed through the union operator and the difference operator b. Because the intersection operator can be expressed through the selection operator and the projection operator c. Because the intersection operator can be expressed through the product operator and the projection operator d. Because the intersection operator can be expressed through the selection operator and the product operator
a
QN=50 (8584) 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
QN=51 (8633) ___ allow the database application to find data fast, without reading the whole table a. Indexes b. Views c. Triggers d. Store-procedures
a
QN=52 (8630) What are the drawbacks of indexes? (a)Indexes require more disk space (b) Indexes make UPDATE, INSERT, DELETE statement slower (c)Indexes have no any drawback (d) Indexes make SELECT statement slower a. (a) and (b) are true b. (a) and (c) are true c. (b) and (c) are true d. (b) and (d) are true
a
QN=53 (9176) The SQL operations that are performed while a connection is active form a ____ a. Session b. Catalog c. Module d. None of the others
a
QN=55 (9168) 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
QN=55 (9182) The aim for the Object-relational database is to bridge the gap between conceptual data modelling techniques such as Entity-relationship diagram (ERD) and object-relational mapping (ORM), which often use classes and inheritance, and relational databases, which do not directly support them a. True b. False
a
QN=57 (9187) A ____ table is a table that is embedded within another table a. Nested b. Primitive c. Parent d. Child
a
QN=57 (9192) ______ is a set of markup declarations that define a document type for SGML-family markup languages (SGML, XML, HTML) a. Document Type Definition b. Document Definition Language c. Document Manipulation Language d. Document Control Language
a
QN=58 (9195) 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
QN=59 (9196) Select the well-formed XML. a. <? xml version = "1.0" ?> <MovieData> <Movie title="StarWar"><Year>1997</Year></Movie> </MovieData> b. <? xml version = "1.0" ?> <MovieData> <Movie title="StarWar"><Year>1997</Year></Movie> </Movies> c. <? xml version = "1.0" ?> <MovieData> <Movie title="StarWar"><Year>1997</Movie></Year> </MovieData> d. All of the others.
a
QN=6 (6827) A _____ is a language for defining data structures a. DDL b. DML c. DCL d. None of the others
a
QN=60 (9207) A ____ is the framework under which data may exist and SQL operations on data may be executed a. SQL Environment b. SQL Statement c. SQL Parser d. SQL Optimizer
a
QN=7 (6826) To update a relation's schema, which one of the following statements can be used? a. ALTER TABLE b. SELECT c. INSERT d. UPDATE
a
QN=7 (6834) 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
QN=8 (6832) 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
Relation R(x,y) currently consists of only one tuple (NULL, NULL). Which of the following queries will produce a nonempty output? That is, at least one tuple will be produced, although the tuple(s) may have NULL's. a. SELECT * FROM R WHERE x IS NULL b. SELECT * FROM R WHERE x = NULL c. SELECT * FROM R WHERE x = y d. SELECT * FROM R WHERE x <> 10
a
Select the right answer. [A] All of the others [B] Tags in XML are text surrounded by triangular brackets (for example, <_>). [C] An XML tag can be a single tag with no matching closing tag (for example. <foo /> [D] Tags in XML comes in matching pairs, with an opening tag like <foo> and a matched closing tag like</foo>
a
Select the right statement [A] All of the others [B] Every constraint has a name. If we don't define constraint's name explicitly, then DBMS automatically generates a name for it [C] We can create constraint on a tuple as a whole. [D] We can create constraint on a single attribute
a
The SQL BETWEEN operator: a. Specifies a range to test. b. Specifies which tables we are selecting from. c. Specifies that a column is a primary key. d. None of the others
a
The table R(X,Y) currently has the following tuples (note there are duplicates).The relation S(A,B,C) has the following tuples: (See picture) Which is the result when we execute the following query: SELECT * FROM R UNION SELECT * FROM S [file:8524.jpg] a. There is an error a b. The output has 15 rows c. The output has 16 rows d. The output has 17 rows
a
To apply a selection to bag: A. We apply the selection condition to each tuple independently. B. None of others. C. We apply the selection condition to each attribute independently. D. All of the other.
a
What does the keyword ESCAPE mean? a. The keyword ESCAPE is used to match any string that contains the characters "%" or "_" b. There is no keyword named ESCAPE c. The keyword ESCAPE is used to match any string that contains the characters "?" or "*" d. The keyword ESCAPE is used to match any string that contains the characters "@" or "$"
a
What is the difference between Where and Having Clause? A.WHERE is for Rows and HAVING is for Groups B.WHERE is for Groups and HAVING is for Rows C.WHERE and HAVING are the same D.We can use aggregation functions in WHERE clause
a
What is the oldest data model? [A] Network Data Model [B] Flat File Data Model [C] Relational Data Model [D] Hierachical Data Model
a
What structure can you implement for the database to speed up table reads? a. indexes b. triggers c. store-procedures d. synonyms
a
When declaring foreign key constraint for relation A thai references relation B. the referenced attribute(s) of the relation B must be declare as_______ [A] UNIQUE or PRIMARY KEY [B] FOREIGN KEY [C] INDEX KEY [D] All of the others
a
When join R and S, we want to display all the records in R we must use: a. LEFT OUTER JOIN a b. RIGHT OUTER JOIN c. INNER JOIN d. None of the others
a
Which of the followings is true? [A] The Entity Relationship (ER) model represents the structure of data graphically [B] The ER model is a low level database design IC] The ER model represents the operation on data [D] All of the others
a
XML files are semi-structured data [A] True [B] False
a
QN=38 (8532) Here are two relations, R(A,B), S(C,D). Their current values are: R A B ------------------- 1 4 2 5 8 6 4 7 S C D ------------------- 0 1 1 0 2 1 5 8 Compute the result of the query: SELECT A, B, C, D FROM R RIGHT OUTER JOIN S ON R.A = S.C Identify, in the list below, 2 rows that appears in the result. a. (null, null, 0, 1) b. (null, null, 5, 8) c. (8, 6, null, null) d. (4, 7, null, null)
a,b
A data model is a notation for describing data or information. And the description generally consist of: [A] 2 parts [B] 3 parts [C] 4 parts [D] 5 parts
b
A relation is a list of tuples [A] True [B] False
b
A weak entity A.does not depend on other entities B.does not have enough key attribute(s) C.is an entity that has not any key-attribute D.None of the others
b
Choose a right answer. [A] A SOL environment is the framework under which data may exist and SQL operations on data may be executed [B] All of the others [C] Within a SQL environment are two special kinds of processes: SQL clients and SQL servers. [D] A SQL environment is a DBMS running at some installation.
b
Choose the right statement [A] XML Schema allows us to declare simple types, such as integer or float and even complex types [B] All of the others [C] XML schema provides us the ability to declare keys and foreign keys. [D] XML Schema is an alternative way to provide a schema for XML documents.
b
Consider a relation with schema R(A, B. C. D) and FD's A-> B. A-> C. C -> D. Which ofthe following is the {A}+ ? [A] {A} [B] {A B C D} [C] {A. B. C} [D] {A.B}
b
Consider the distrubutive law, that holds for set relation: (R U S)- T =(R-T)U(S-T) The above distributive still hold for bag relations? a. TRUE B. FALSE
b
Consider the following statement: "When drawing ERD, if an entity has no non-key attribute and it is the 'one' in many-one relationship, then we should set it to the attribute of other entities" That above statement describes which principle? A.Avoid Redundancy Principle B.Picking the right kind of element principle C.Limit the use of weak entity sets principle D.Faithfulness principle
b
DBMS stands for what? [A] Database Managing Systems [B] Database Management System [C] Database Manage System [D] Database Managable System
b
Every row and value must agree with all constratints right after the transaction is complete. The above describes which propety of a transaction? A.Isolation B.Consistency C.Atomic. D. Durability
b
Give the relation R(XYZT) with the following FD's: XY -> Z ; XYT -> Z ; XYZ -> T ; XZ -> T Determine the primary key for R and then choose the correct statement [A] R is in BCNF [B] R is not in BCNF
b
Given a relation R(A.B.C.D). Which of the followings is trivial? [A] A->BCD [B] A->->BCD [C] A->AB [D] A->->AB
b
Given the relation Employee(SSN. FNAME. LNAME. SALARY. DepartmentNo). Select the right query below to count the number of employees in each department [A] SELECT COUNTf) FROM Employee [B] SELECT DepartmentNo. COUNT(*) FROM Employee GROUP BY DepartmentNo [C] SELECT DepartmentNo. COUNT(*) FROM Employee [D] None of the others
b
Here are three relations, R(A,B), S(C,D), and T(E,F). Their current values are: R A B ------------------- 0 1 1 0 1 1 S C D ------------------- 0 1 1 0 1 1 T E F ------------------- 0 1 1 0 1 1 Compute the result of the query: SELECT A, F, SUM(C), SUM(D) FROM R, S, T WHERE B = C AND D = E GROUP BY A, F HAVING COUNT(*) > 1 Identify, in the list below, the row that appears in the result. A.(1,1,2,1) B.(1,1,2,2) C.(1,1,1,1) D.None of the others
b
How many properties we must use to measure the quality of a transaction? A.6 B.4 C.3 D.5
b
In databse design precesses, data requirements are expressed through...... (a) Schema Design (b)ERD (c)UML (d) Table Design A. (c) and (d) B. (b) and (c) C. (a) and (b) D. (d) and (a)
b
In relational data model, an attribute is a column [A] True [B] False
b
Look at the following data for table R: A B C 1 1 2 1 1 2 1 1 3 Choose all correct answers [A] R is not a relation [B] R is a relation [C] R has no key
b
Look at this line: MOVIES (Id, Name, Description) What the above represent? [A] A relation [B] A schema [C] A schema instance [D] A relation instance
b
QN=17 (8004) What is the benefit of "de-normalization"? a. "de-normalization" has no benefit b. The main benefit of de-normalization is improved performance with simplified data retrieval (this is done by reduction in the number of joins needed for data processing) c. The main benefit of de-normalization is eliminating redundant information from a table and organizing the data so that future changes to the table are easier
b
QN=19 (8002) 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
QN=2 (6801) 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
QN=20 (6821) Which one of the following is NOT a DML command? a. DELETE b. GRANT c. INSERT d. UPDATE
b
QN=22 (6811) The relational operator that adds all possible pairs of rows from two tables is known as the .... operator. a. union b. product c. join d. selection
b
QN=24 (8238) Consider the law, that holds for set relations: T intersect(R union S) = (T intersect R) union (T intersect S) The above law still hold for bag relations? a. True b. False
b
QN=25 (7969) Consider a relation with schema R(A, B, C, D) and FD's BC -> D, D -> A, A -> B. Which of the following is the key of R? a. BD b. BC c. D d. AB
b
QN=26 (8017) 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
QN=3 (6802) 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
QN=32 (7981) Suppose we have a relation R(ABCD) with FD's: BC -> A ; AD -> C ; CD -> B ; BD -> C a. R is in BCNF b. R is not in BCNF c. All of the others d. None of the others
b
QN=35 (8503) Given the relation Employee(SSN, FNAME, LNAME, SALARY, DepartmentNo). Select the right query below to count the number of employees in each department. a. SELECT COUNT(*) FROM Employee b. SELECT DepartmentNo, COUNT(*) FROM Employee GROUP BY DepartmentNo c. SELECT DepartmentNo, COUNT(*) FROM Employee d. None of the others
b
QN=12 (6816) Data Definition language (DDL) is used to ...... a. query database and modify the database b. connect to database and query database c. declare database schemas d. All of the others
c
QN=37 (8611) Look at the following tables and then choose the correct statment: ARTISTS Airtist_id Airtist_Name ----------------------------------- 1 Bono 2 Cher ALBUM artist_id Album_name ------------------------------------ 3 Eat the rich a. The above picture is an example of a database that has not enforced referential integrity b. The above picture is an example of a database that has not enforced entity integrity c. The above picture is an example of a database that has not enforced domain integrity d. All of the others
b
QN=38 (7977) The relation R(ABCD) has following FDs: { AB -> C ; ABD -> C ; ABC -> D ; AC -> D} Choose a correct statement about R? a. R is in 3NF b. R is not in 3NF c. R is in BCNF
b
QN=4 (6793) A ______ is a collection of programs that enables user to create and maintain databases. In other words, it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the databases for various applications a. MSSQL b. DBMS c. DBS d. DB2
b
QN=41 (8569) Suppose relation R(A,B). Choose the SQL statement that is equivalent to the following RA expression: [file:8569.jpg] a. SELECT * FROM R b. SELECT (A+B) AS C FROM R WHERE (A+B) > 10 c. SELECT (A+B) AS C FROM R d. There is not any choice
b
QN=42 (8552) Choose one correct statement: a. Two null values are equal b. Comparisons between two null values, or between a NULL and any other value, return unknown c. Comparisons between two null values, or between a NULL and any other value, return FALSE
b
QN=44 (8585) Suppose R and S are 2 relations. R is the parent of S. And the relationship between R and S is set to "ON DELETE CASCADE". This means that: a. We can delete a row from R if that row has children in S (and in this case, the database server will raise up an error) b. We can delete a row from R although that row has children in S (and in this case, all the children will be deleted too)
b
QN=48 (8573) Suppose we have a relation instance R(A,B,C) as following: R A B C ---------------------------------- 1 2 3 4 5 6 7 8 9 Which is the result of the query: SELECT SUM(B) FROM R WHERE C > 10 a. 0 b. NULL c. 3 d. 10
b
QN=5 (6810) Today, the two important data models are: a. The semi-structured data model (including XML and related standards) and the network data model b. The relational data model (including object-relational extensions) and the semi-structured data model (including XML and related standards) c. The network data model and the flat file data model d. The flat file data model and the semi-structured data model (including XML and related standards)
b
QN=52 (8616) 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
QN=53 (8624) Well-designed ____ can reduce disk I/O operations and consume fewer system resources therefore improving query performance a. Triggers b. Indexes c. Views d. Stored Procedures
b
QN=58 (9198) A ____ document defines the XML document structure with a list of legal elements and attributes a. XML b. DTD c. XSLT d. SGML
b
QN=8 (6829) What is another term for a row in a relational table? a. Attribute b. Tuple c. Field d. Relation
b
QN=9 (6806) A person who is responsible for the structure or schema of the database is called: a. an end user b. a database administrator c. a database analyst d. all of the others
b
Regardless of whatever any other transaction is doing, a transaction must be able to continue with the exact same data set it started with. The above describes which property of a transaction? a. Atomic b. Isolation c. Consistency d. Durability
b
Selecl Ihe right syntax for HAVING clause in SOL [A] SELECT <list of attributes> FROM <list of tables> WHERE <conditions on tuples> HAVING <conditions on groups> GROUP BY <list of attributes> [B] SELECT <list of attributes> FROM <list of tables> WHERE <conditions on tuples> GROUP BY <list of attributes> HAVING <conditions on groups> [C] SELECT < list of attributes> FROM < list of tables> HAVING <conditions on groups> WHERE <conditions on tuples> GROUP BY <list of attributes> [D] All of the others
b
Select the well-formed XML [A] All of the others [B] <? xml version = "1.0" ?> <MovieData> <Movie tiHe="StarWar*><Year>1997</Yearx/MovJe> </MovieData> [C] <? xml version - "1 0' ?> <MovieData> <Movie Me-'StarWaf*><Year>1997</Year></Movie> </Movies> [D] <? xml version = 1 0 7> <MovieData> <Movie trtle-"StarWar"><Year>1997</Movie></Year> </MovieData>
b
The relation R(A,B) may have duplicate tuples. Choose the query that create non-duplicated results, regardless of what tuples R contains? A.SELECT A, B FROM R B.SELECT A, B FROM R GROUP BY A, B C.SELECT A FROM R WHERE A NOT IN (SELECT B FROM R) D.SELECT TOP 3 A, B FROM R
b
To create a constraint (for example, referential integrity constraint) on a relation, the owner ofthe schema must have [A] UNDER privilege [B] REFERENCES privilege [C] UPDATE privilege [D] EXECUTE privilege
b
When an entity is called "weak"? (a) When it is used to represent weak objects, such as patients, elders (b) When all of its attributes can not identify itself (c) When It always needs support from other entity (d) When It is not really necessary in the ERD a.(a) and (b) are correct b.(b) and (c) are correct c.(c) and (d) are correct d.(d) and (a) are correct
b
When drawing an ERD: (a)Entity sets and their attributes should reflect reality (b)Redundancy is not important, so we can ignore it (c) Avoid introducing more elements into the design than is absolutely necessary (d) Choosing the right relationships A.(a) and (b) and (c) are correct B.(a) and (c) and (d) are correct C.(a) and (b) and (d) are correct D.(b) and (c) and (d) are correct
b
_______authorizes access to database, coordinate, monitor its use, acquiring software, and hardware resources. [A] All of the others [B] Database administrator [C] Database designer [D] Database end-user
b
QN=33 (8528) Suppose relation R(A,B) has the tuples: A B ------------------- 10 x 30 y 50 z 70 t and the relation S(B,C,D) has tuples: B C D ------------------------------------ x 40 60 z 60 80 z 50 50 z 70 90 Compute the right outer join of R and S, where the condition is: R.B = S.B. Then identify 2 tuples of R that do not appear in the computed result. a. (10,x) b. (30,y) c. (50,z) d. (70,t)
b,d
A weak entity: [A] must have total participation in an identifying relationship [B] does not have a key attribute(s) [C] both (a) and (b) [D] none of the above
c
Choose a right answer [A] When a privilege is granted, it cannot be revoked [B] Privileges cannot be granted on a view [C] An authorization ID may be granted privileges from others or may grve its privileges to others [D] All of the others
c
Choose the right statement to grant the INSERT and SELECT privileges on table Movies to users torn' and jerry' [A] GRANT SELECT. INSERT on Movies [B] GRANT SELECT. INSERT on Movies TO torn, jerry CASCADE [C] GRANT SELECT. INSERT on Movies TO torn, jerry WITH GRANT OPTION [D] GRANT SELECT. INSERT on Movies TO ALL
c
Exception handler in PSM is defined as follows: DECLARE <where to go next> HANDLER FOR condition list> <statement> The <where to go next> clause can be: [A] UNDO [B] EXIT [C] All of the others [D] CONTINUE
c
Given relation U(A, B, C) that has 2 tuples (1,2,3) and (4,5,6), and relation V(B(C, D) that has 2 tuples (2,3,10) and (2,3,11). Choose the right answer below; [A] None of the others. [B] The outer join of U and V is the relation R(A, B, C, D) that has 2 tuples (1.2, 3.10) and (1,2, 3,11). [C] The outer join of U and V is the relation R(A. B. C. D) that has 3 tuples (1.2.3.10) .(1.2.3.11) and (4.5.6. NULL). [D] The outer join of U and V is the relation R(A. B. C. D) that has only 1 tuple (NULL. 4.5.6).
c
Given relations Movies(title, year, length, genre. studioName. producer#). MovieExec(name. address. cert#). and Studio(name. address. presC#). Suppose we have the materialized view that finds the name - ofthe producer of a given movie as follows: CREATE MATERIALIZED VIEW MovieProd AS SELECT title, year, name FROM Movies. MovieExec WHERE producer# - cert# Which of the following modification will affect the MovieProd materialized view? [A] Insert a new tuple into Studio [B] Delete a tuple from Studio [C] Insert a new tuple into Movies or delete a tuple from Movies [D] None of the others
c
Given relations R(A,B) and S(B,C,D). The result of natural join of the relations R and S has a. Only attribute B b. Only two attributes R.B and S.B c. Attributes A, B, C, D d. None of the others
c
Given the diagram below,using the nulls method we can create a single relation whose schema is..... A.Movies(title,year,length,genre) B.Movies(title,year,length,genre,cartoons) C.Movies(title,year,length,genre,weapon) D.Movies(title,year,length,genre,murder)
c
Given the relation Movies(title, year, length, genre. studioName). Select the right query to create a View with the titles and studio names of all movies that were produced in 1980 [A] CREATE VIEW OldMovies SELECT title. studioName FROM Movies WHERE year-1980 [B] CREATE VIEW OldMovies SELECT title, year FROM Movies WHERE year=1980 [C] CREATE VIEW OldMovies AS SELECT title. studioName FROM Movies WHERE year=1980 [D] None of the others
c
Given the relation schema R(XYZT) and functional dependencies F = {X->Z, T->Y}. Which functional dependency causes a violation of second normal form (2NF) ? [A] X->Z [B] T->Y [C] both X->Z and T->Y [D] none of the above
c
In PSM. the difference between 3 stored procedure and a function is that [A] A function has the return statement. [B] We can declare local variables in a function. [C] All of the others [D] Loops are not allowed in a function.
c
QN=1 (6807) What is a graph database? a. A graph database is a database that uses tree structures with nodes to represent and store information b. A graph database is a database that uses table structures to represent and store information c. A graph database is a database that uses graph structures with nodes, edges and properties to represent and store information d. None of the others
c
QN=10 (6809) A database administrator (DBA) is a person that is also known by the title: a. Database Analyst b. Database Tuner c. Database Coordinator or Database Programmer d. Database Modeller
c
QN=17 (6831) What is a primary key? a. A primary key is the field(s) in a table that uniquely defines that table in a database b. A primary key is the field(s) in a table that is used to establishes a relationship between two tables c. A primary key is the field(s) in a table that uniquely defines the row in the table d. A primary key is the field(s) in a table that is used to establishes a relationship between two databases
c
QN=18 (7975) Let R(A,B,C,D) with the following FDs: {AB->C, AC->B, AD->C} Choose a correct statement about R: a. R is in BCNF b. R is in 3NF c. R is in 2NF d. None of the others
c
QN=23 (7956) Let R(ABCDEFGH) satisfies the following functional dependencies: A -> B, CH -> A, B -> E, BD -> C, EG -> H, DE -> F. Which of the following FDs is also guaranteed to be satisfied by R? a. CGH -> BF b. ACG -> DH c. ADG -> CH d. BCD -> FH
c
QN=27 (7971) Given the relation R(ABCDE) with the following FD's: D -> C, CE ->A, D ->A, and AE ->D Which of the following attribute set is a key? a. ABCDE b. CDE c. ABE d. BD
c
QN=27 (8030) The binary relationship between classes in UML is called ... a. Aggregation b. Composition c. Association d. Relation
c
QN=27 (8500) Suppose the relation S(B,C,D) has tuples: B C D ----------------------------------- a 4 6 c 6 8 c 5 5 e 9 9 f 10 10 c 7 9 Compute the result of the following query: SELECT D, SUM(C) FROM S GROUP BY D Choose rows that are appear in the computed result a. (9,12) b. (9,14) c. (9,16) d. (9,18)
c
QN=28 (8509) Column A of a relation has the following list of values in the six rows of the table: NULL, NULL, 10, 10, 20, 30 In SQL Server, which of the following is the correct value of AVG(DISTINCT A)? a. 15 b. NULL c. 20 d. 10
c
QN=31 (8523) When we apply set operators (UNION, INTERSECT, EXCEPT) to two relations R and S, which conditions on R and S must be satisfied? a. R and S must have schemas with identical sets of attributes and the types (domains) for each attributes must be the same in R and S b. Before we compute the set-theoretic union, intersection, or difference of sets of tuples, the columns of R and S must be ordered so that the order of attributes is the same for both relations c. All of the others
c
QN=33 (8576) The IN SQL keyword a. Is used with the DISTINCT SQL keyword only b. Is used with the INSERT SQL keyword only c. Determines if a value any of the values in a list or a sub-query d. Defines the tables we are selecting or deleting data from
c
QN=35 (8547) 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
Suppose relation R(a,b,c) has the following tuples: A B C ----------------------------------- 1 1 3 1 2 3 2 1 4 2 3 5 2 4 1 3 2 4 3 3 6 Which tuple is contained in the result of the following query: SELECT a, COUNT(DISTINCT B) FROM R GROUP BY a HAVING SUM(B) >3; A.(2,10) B.(3,7) C.(2,3) D.(3,12)
c
QN=40 (7992) Normalization is a process of analyzing the given relation schema based on their Functional Dependencies (FDs) and primary keys to achieve the following: a. Minimizing redundancy b. Minimizing insertion anomalies c. All of the others d. Minimizing deletion and update anomalies
c
QN=40 (8560) A database transaction, by definition, must be ACID (atomic, consistent, isolated and durable). What does "Durable" mean? a. "Durable" means that: Transactions provide an "all-or-nothing" proposition, stating that each work-unit performed in a database must either complete in its entirety or have no effect whatsoever b. "Durable" means that: Transactions must not violate any integrity constraints during its execution c. "Durable" means that: Transactions that have committed will survive permanently d. All of the others
c
QN=42 (8575) What is the difference between the WHERE and HAVING SQL clauses? a. The WHERE and the HAVING clauses are identical b. The HAVING SQL clause condition(s) is applied to all rows in the result set before the WHERE clause is applied (if present). The WHERE clause is used only with SELECT SQL statements and specifies a search condition for an aggregate or a group c. The WHERE SQL clause condition(s) is applied to all rows in the result set before the HAVING clause is applied (if present). The HAVING clause is used only with SELECT SQL statements and specifies a search condition for an aggregate or a group d. None of the others
c
QN=47 (8609) 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
QN=56 (9186) Select the right statement to declare MovieStar to be a relation whose tuples are of type StarType. Note: StarType is a user-defined type that has its definition as follows: CREATE TYPE StarType AS ( name CHAR(30), address CHAR(100) ); a. CREATE TABLE MovieStar (name StarType ); b. CREATE TABLE MovieStar (name StarType PRIMARY KEY ); c. CREATE TABLE MovieStar OF StarType (); d. None of the others
c
QN=6 (6814) 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
QN=60 (9211) A _____ specifies which characters are "less than" which other characters a. Domains b. Character set c. Collation d. Stored procedure
c
Select the right statement to declare MovieStar to be a relation whose tuples are of type StarType. Note; StarType is a user-defined type that has its definition as follows; CREATE TYPE StarType AS ( nameCHAR(30). address CHAR(IOO) }; [A] CREATE TABLE MovieStar (name StarType). PI CREATE TABLE MovieStar (name StarType PRIMARY KEY); [C] CREATE TABLE MovieStar OF StarType Q; [D] None of the others
c
Suppose an updatable view ParamountMovies is associated with Movies relation. Choose a correct answer. a. Drop Movies relation also delete the view ParamountMovies b. Drop ParamountMovies also delete Movies c. An update on ParamountMovies is translated into Movies d. None of the others
c
Suppose relations R(A<B) and S(B,C,D) are as follows: R= A B 1 2 3 4 5 6 S= B C D 4 5 1 6 7 2 8 9 3 Compute the full outer join on B, where R is the left operand and S is the right operand. Find the correct statement in the list below. A. The full outer has 6 tuples. B. The full outer has 3 tuples. C. The full outer has 4 tuples. D. The full outer has 5 tuples.
c
The relational operator that yields all possible pairs of rows from two tables is known as a _ [A] Union [B] Selection [C] Product [D] Join
c
The result of (UNKNOWN OR TRUE) is [A] UNKNOWN [B] FALSE [C] TRUE [D] NULL
c
What SQL keyword can be use to return data from two non-related tables as a combined set of rows? A. DISTINCT ALL B. DISTINCT C. UNION ALL D. COMBINED
c
What does the following SQL statement do: SELECT Customer, COUNT(Order) FROM Sales GROUP BY Customer HAVING COUNT(Order) > 5 A.Selects the total number of orders from the Sales table, if this number is greater than 5 B.Selects all Customers from the Sales table C.Selects all customers from table Sales that have made more than 5 orders. D.None of the other three
c
What is a view? a. A view is a database diagram b. A view is a special stored procedure executed when certain event occurs c. A view is a virtual table which results of executing a pre-compiled query. A view is not a part of the physical database schema, while the regular tables are. d. None of the others
c
Which of the following statements is true? [A] I3NF implies BCNF [B] Multi-valued Dependency (MVD) implies Fourth Normal form (4NF) [C] 4NF implies BCNF and BCNF implies 3NF [D] None of the others
c
5. The ER model is meant to a) replace relational design b) enable detailed descriptions of data query processing c) enable low level descriptions of data d) be close to a users perception of the data
d
Choose a right answer [A] The object-relational model is the extension of the relation model with new features such as structured types, methods, identifiers for tuples, and references [B] Object-relation model allows a non-atomic type that can be a relation schema which is called nested relation [C] In object-relational model, the type of an attribute can be a reference to a tuple with a given schema or a set of references to tuples with a given schema [D] All of the others
d
Choose right answer(s). [A] NULL value is unknown, inapplicable, or withheld [B] Comparisons with NULL values will return UNKNOWN [C] Arithmetic operators on NULL values will return a NULL value [D] All of orther
d
Choose the in-correct statement: a. In SQL Server, every DML operation is a transaction regardless of whether it has a BEGIN TRANSACTION or not b. COMMITTING a transaction makes permanent the changes resulting from all SQL statements in the transaction c. ROLLING back a transaction rejects any of the changes resulting from the SQL statements in the transaction d. When the sequence of tasks is complete, the SAVE POINT closes the transaction
d
Choose the right statement [A] Sub-queries return a single constant this constant can be compared with another value in a WHERE clause; [B] Sub-queries return relations, that can be used in WHERE clause [C] Sub-queries can appear in FROM clauses, followed by a tuple variable [D] All of the others
d
Choose the right statement [A] The action associated with the trigger executes no matter what the condition is hold or not [B] Triggering events do not support INSERT and DELETE. [C] All of the others. [D] When the trigger is awakened, it tests a condition. If the condition is satisfied, the action associated with the trigger is executed.
d
Consider a relation with schema R(A, B, CD) and FD's BC-> D, D-> A, A-> B. Which of the following is the key of R? [A] BD [B] D [C] AB [D] BC
d
Consider the Dalalog rule H(xy) <- Sfx. y) AND x > 2 AND y < 6. Relation S(x y) has 3 tuples (2.3). (3.5). and (4.6). What is about H? [A] H has a tuple (2.3) [B] H has 3 tuples (2.3) and (3.5) and (4.6) [C] H has 2 tuples (2.3) and (3.5) [D] H has a tuple (3.5)
d
Four characteristics of transactions are [A] None of the others [B] Read uncommitted, Read committed, Repeatable read, Serializable [C] Atomicity. Isolation. Concurrency. Durability [D] Atomicity. Isolation. Consistency. Durability
d
Given relations R(A.B) and S(B.C.D). The result of natural join of the relations R and S has [A] Only two attributes R B and SB [B] None of the others [C] Only attribute B [D] Attributes A B. C. D
d
How many data models mentioned in our database course? [A] 3 [B] 4 [C] 5 [D] 6
d
In Java Database Connectivity (JDBC). before we can execute SQL statements), we need to _ [A] Create a cursor. [B] Create an environment [C] Create a description. [D] Establish a connection to the database and create statement(s)
d
In the three-tier architecture, the database tier's function is to [A] All of the others. [B] Execute the business logic of the organization operating the database. [C] Manage the interactions with the user. [D] Execute queries that are requested from the application tier.
d
QN=14 (6818) Which of the followings is part of data model? a. Structure of the data b. Operations on the data c. Constraints on the data d. All of the others
d
QN=18 (8022) 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
QN=20 (8005) 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
QN=24 (8029) 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
QN=26 (7963) Given the relation schema R(A,B,C) and functional dependencies F = {AB-> C, B->A, C->B}. Which attribute(s) is/are prime? a. only A b. only B c. A and B d. B and C
d
QN=32 (8526) How many JOIN conditions are necessary to combine five tables based on common attributes? a. 1 b. 2 c. 3 d. 4
d
QN=34 (8501) Suppose the relation S(B,C,D) has tuples: B C D ------------------------------------ a 4 6 c 6 8 c 5 5 e 9 9 F 10 10 c 7 9 Which one of the followings will appear in the result of the following query: SELECT B, SUM(C) FROM S GROUP BY B a. (c,11) b. (c,13) c. (c,12) d. (c,18)
d
QN=36 (8505) Suppose the relation S(B,C,D) has tuples: B C D ------------------------------------ a 4 6 c 6 8 c 5 5 e 9 9 f 10 10 c 7 9 What row that appears in the result of the following query: SELECT SUM(C), SUM(D) FROM S WHERE D < 9 AND D > 5 a. (10,11) b. (10,12) c. (10,13) d. (10,14)
d
QN=37 (8550) What is the value of the query: SELECT 'Nancy' + NULL + 'Smith' when evaluated on Microsoft SQL Server? a. 'Nancy Smith' b. 'Nancy' c. 'NancySmith' d. NULL
d
QN=43 (8599) 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
QN=44 (8007) Look at the following statements: (a)All relations in 3NF are also in 2NF (b)All relations in 2NF are also in 1NF (c)All relations in 1NF are also in BCNF (d)All relations in 1NF are also in 3NF a. (b) and (d) are true b. (a) and (c) are true c. (a) and (d) are true d. (a) and (b) are true
d
QN=46 (7997) Which of the following are guidelines for designing the relational schema ? a. Reduce the redundant values in tuples b. Reduce the NULL values in tuples c. Always make relations 3NF d. All of the others
d
QN=46 (8559) A database transaction, by definition, must be ACID (atomic, consistent, isolated and durable). What does "Isolated" mean? a. "Isolated" means that: Transactions provide an "all-or-nothing" proposition, stating that each work-unit performed in a database must either complete in its entirety or have no effect whatsoever b. "Isolated" means that: Transactions must not violate any integrity constraints during its execution c. "Isolated" means that: Transactions that have committed will survive permanently d. "Isolated" means that: how/when the changes made by one operation in one transaction become visible to other concurrent operations in other transactions
d
QN=50 (8620) Select the most correct answer a. An index is a data structure used to speed access to tuples of a relation, given values of one or more attributes b. The key for index can be any attribute or set of attributes, and need not be the key of the relation c. We can think of the index as a binary search tree of (key, locations) pairs in which a key a is associated with a set of locations of the tuples d. All of the others.
d
QN=54 (9178) 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
QN=56 (9189) Choose the correct statement: a. A User-Defined Type (UDT) in SQL can be the type of a table b. A UDT can be the type of an attribute belonging to some table c. The form of UDT definition is: CREATE TYPE T AS (<primitive type | attribute declarations>) d. All of the others
d
QN=6 (6798) Today, in a modern DBMS, the queries are parsed and optimized by a. all of the others b. execution engine c. buffer manager d. query compiler
d
QN=9 (7961) 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
Referential integrity Constraints control relationships between .... a. attributes in a table b. operations of an object c. database instances d. tables in a database
d
Select the right answer [A] Virtual views do not exist physically [B] Virtual views are defined by an expression like a query [C] Virtual views can be queried and can even be modified [D] All of other
d
Select the valid query to declare the foreign key presC# of the relation Studiolname. address. presC#) that references the cert of the relation MovieExeclname. address. cert#. netWorth): [A] All of the others. [B] CREATE TABLE Studio (name CHAR(30) PRIMARY KEY. address VARCHAR(256). presC# INT FOREIGN KEY): [C] CREATE TABLE Studio (name CHAR(30) PRIMARY KEY. address VARCHAR(256). presC# INT UNIQUE KEY REFERENCES MovieExec): [D] CREATE TABLE Studio (name CHAR(30) PRIMARY KEY. address VARCHAR(256). presC# INT REFERENCES Movie Exec (cert#));
d
When the Relational Data Model first proposed? [A] 1940 [B] 1950 [C] 1960 [D] 1970
d
Which of the following statements is the most correct? a. Poorly designed indexes and a lack of indexes are primary sources of database application bottlenecks. b. Designing efficient indexes is paramount to achieve good database and application performance c. The selection of the right indexes for a database and its workload is a complex balancing act between query speed and update cost d. All of the others
d
With SQL, how do you select all the records from a table named "Persons" where the value of the column "FirstName" starts with an "a"? a. SELECT * FROM Persons WHERE FirstName='a' b. SELECT * FROM Persons WHERE FirstName LIKE '%a' c. SELECT * FROM Persons WHERE FirstName='%a%' d. SELECT * FROM Persons WHERE FirstName LIKE 'a%'
d
QN=16 (7991) 3NFconcept 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
QN=49 (8589) 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
Why we should use stored procedures? a. They allow faster execution b. They can reduce network traffic c. They allow modular programming d. They can be used as a security mechanism e. All of the others
e
