13986861
Descripción
Test por Brandon Gagon, actualizado hace más de 1 año
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Creado por Brandon Gagon
hace alrededor de 7 años
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Pregunta 1
Pregunta
Which of the following is a benefit of using a DBMS?
Respuesta
-
They provide full security to data using private/public key encryption
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They create automatic backups
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They help create an environment for end users to have access to more data
-
They provide seamless Internet access to database data
Pregunta 2
Pregunta
The hierarchical database model is based on a ____.
Respuesta
-
tree structure
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lack of a parent segment
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lack of a child segment
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matrix
Pregunta 3
Pregunta
Because an RDBMS hides the system's complexity from the user/designer, ____.
Respuesta
-
it does not exhibit data independence
-
it does not exhibit structural independence
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data management is easier
-
data management is very difficult
Pregunta 4
Pregunta
The ERD is used to graphically represent the ____ database model.
Respuesta
-
condensed
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physical
-
logical
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conceptual
Pregunta 5
Pregunta
The property of ____ enables an entity subtype to inherit the attributes and relationships of the supertype.
Respuesta
-
subtype discriminator
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inheritance
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specialization hierarchy
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entity supertype
Pregunta 6
Pregunta
At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a ____ relationship.
Respuesta
-
none
-
1:1
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1:M
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M:N
Pregunta 7
Pregunta
Which command would be used to delete the table row where the P_Code = '2238/QPD'?
Respuesta
-
DELETE FROM PRODUCT WHERE P_CODE = '2238/QPD';
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REMOVE FROM PRODUCT WHERE P_CODE = '2238/QPD';
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ERASE FROM PRODUCT WHERE P_CODE = '2238/QPD';
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ROLLBACK FROM PRODUCT WHERE P_CODE = '2238/QPD';
Pregunta 8
Pregunta
Which command is used to select partial table contents?
Respuesta
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SELECT <column(s)> FROM <Table name> WHERE <Item>;
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LIST <column(s)> FROM <Table name> WHERE <Conditions>;
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SELECT <column(s)> FROM <Table name> WHERE <Conditions>;
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LIST<column(s)> FROM <Table name> WHERE <Item>;
Pregunta 9
Pregunta
Which query will output the table contents when the value of V_CODE is equal to 21344?
Respuesta
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SELECT P_DESCRIPT, P_INDATE, P_PRICE, V_CODE FROM PRODUCT WHERE V_CODE <> 21344;
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SELECT P_DESCRIPT, P_INDATE, P_PRICE, V_CODE FROM PRODUCT WHERE V_CODE <= 21344;
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SELECT P_DESCRIPT, P_INDATE, P_PRICE, V_CODE FROM PRODUCT WHERE V_CODE = 21344;
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SELECT P_DESCRIPT, P_INDATE, P_PRICE, V_CODE FROM PRODUCT WHERE V_CODE => 21344;
Pregunta 10
Pregunta
What is the command used to list the P_CODE, P_DESCRIPT, P_INDATE, and P_PRICE fields from the Product table in ascending order by P_PRICE?
Respuesta
-
SELECT P_CODE, P_DESCRIPT, P_INDATE, P_PRICE FROM PRODUCT SEQUENCE BY P_PRICE;
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SELECT P_CODE, P_DESCRIPT, P_INDATE, P_PRICE FROM PRODUCT LIST BY P_PRICE;
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SELECT P_CODE, P_DESCRIPT, P_INDATE, P_PRICE FROM PRODUCT ORDER BY P_PRICE;
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SELECT P_CODE, P_DESCRIPT, P_INDATE, P_PRICE FROM PRODUCT ASCENDING BY P_PRICE;
Pregunta 11
Pregunta
The basic SQL aggregate function that gives the total of all values for a selected attribute in a given column is ____.
Respuesta
-
COUNT
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MIN
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MAX
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SUM
Pregunta 12
Pregunta
____ is used to tally the number of specific "values" of an attribute.
Respuesta
-
SUM
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TOTAL
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COUNT
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ADD
Pregunta 13
Pregunta
UPDATE tablename
*****
[WHERE conditionlist];
What command replaces the ***** in the above statement?
Respuesta
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SET columnname = expression
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columnname = expression
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expression = columnname
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LET columnname = expression
Pregunta 14
Pregunta
When using a(n) ____ join, only rows that meet the given criteria are returned.
Respuesta
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full
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inner
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outer
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set
Pregunta 15
Pregunta
What is the syntax for a left outer join?
Respuesta
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SELECT column-list FROM table1 OUTER JOIN table2 LEFT WHERE join-condition
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SELECT column-list FROM table1 LEFT [OUTER] JOIN table2 ON join-condition
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SELECT column-list WHERE LEFT table1 = table 2
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SELECT column-list FROM table1 LEFT table2 [JOIN] WHERE join-condition
Pregunta 16
Pregunta
In subquery terminology, the first query in the SQL statement is known as the ____ query.
Respuesta
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outer
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left
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inner
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base
Pregunta 17
Pregunta
In a subquery, which query is executed first?
Respuesta
-
leftmost
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rightmost
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innermost
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outermost
Pregunta 18
Pregunta
Creating the conceptual design, selecting DBMS software, creating the logical design, and creating the physical design are part of the ____ phase.
Respuesta
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database initial study
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database design
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implementation and loading
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testing and evaluation
Pregunta 19
Pregunta
Which of the conceptual design steps defines entities, attributes, and relationships?
Respuesta
-
Database analysis and requirements
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Entity relationship modeling and normalization
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Data model verification
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Distributed database design
Pregunta 20
Pregunta
What is the primary objective of database design?
Respuesta
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To create the most efficient database possible
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To create complete, normalized, nonredundant, and fully integrated conceptual, logical, and physical database models
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To create the fastest queries
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To be able to add data quickly
Pregunta 21
Pregunta
The most common algorithms for concurrency control are locks, ____ stamping, and optimistic methods.
Respuesta
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date
-
time
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hour
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minute
Pregunta 22
Pregunta
____ requires that all operations of a transaction be completed.
Respuesta
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Specificity
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Atomicity
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Durability
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Time Stamping
Pregunta 23
Pregunta
The ____ establishes the order in which the operations within concurrent transactions are executed.
Respuesta
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transaction log
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timer
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lock manager
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scheduler
Pregunta 24
Pregunta
When is the implicit beginning of a transaction?
Respuesta
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When the database is started
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When a table is accessed for the first time
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When the first SQL statement is encountered
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When the COMMIT command is issued
Pregunta 25
Pregunta
A(n) ____ phase in a two-phase lock is when a transaction releases all locks and cannot obtain any new lock.
Respuesta
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growing
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shrinking
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locking
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unlocking
Pregunta 26
Pregunta
What is a consistent database?
Respuesta
-
One in which all tables have foreign keys
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One in which all data integrity constraints are satisfied
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One in which all tables are normalized
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One in which all SQL statements only update one table at a time
Pregunta 27
Pregunta
A transaction acquires a ____ prior to data access.
Respuesta
-
grain
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timestamp
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lock
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key
Pregunta 28
Pregunta
Changes are permanently applied to the database during the ____ phase of a transaction.
Respuesta
-
commit
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write
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input
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output
Pregunta 29
Pregunta
The phenomenon of ____ occurs when two transactions, T1 and T2, are executed concurrently and the first transaction (T1) is rolled back after the second transaction (T2) has already accessed the uncommitted data—thus violating the isolation property of transactions.
Respuesta
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lost updates
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uncommitted data
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transaction failure
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inconsistent retrieval
Pregunta 30
Pregunta
____ occur when a transaction calculates some summary (aggregate) functions over a set of data while other transactions are updating the data.
Respuesta
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lost updates
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uncommitted data
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transaction failures
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inconsistent retrievals
Pregunta 31
Pregunta
The scheduler facilitates data ____ to ensure that two transactions do not update the same data element at the same time.
Respuesta
-
durability
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isolation
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atomicity
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serializability
Pregunta 32
Pregunta
Which is not a DML statement?
Respuesta
-
CREATE TABLE
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SELECT
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INSERT
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DELETE
Pregunta 33
Pregunta
What feature is a DDBMS disadvantage?
Respuesta
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Data is located near the "greatest demand" site
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Growth facilitation
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Reduced operating cost
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lack of standards
Pregunta 34
Pregunta
What feature is a DDBMS advantage?
Respuesta
-
Greater difficulty in managing the data environment
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Less danger of a single-point failure
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Increased training cost
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Complexity of management and control
Pregunta 35
Pregunta
____ distributed database systems integrate different types of centralized DBMSs over a network.
Respuesta
-
Homogeneous
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Heterogeneous
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Fully homogeneous
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Fully heterogeneous
Pregunta 36
Pregunta
____ transparency allows a transaction to update data at several network sites.
Respuesta
-
Transaction
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Distribution
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Failure
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Performance
Pregunta 37
Pregunta
____ transparency ensures that the system will continue to operate in the event of a node failure.
Respuesta
-
Transaction
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Distribution
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Failure
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Performance
Pregunta 38
Pregunta
The ____ contains the description of the entire database as seen by the database administrator.
Respuesta
-
distributed global dictionary
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distributed data dictionary
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distributed global schema
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distributed data schema
Pregunta 39
Pregunta
____ query optimization means that the DDBMS finds the most cost-effective access path without user intervention.
Respuesta
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Static
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Dynamic
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Automatic
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Commit
Pregunta 40
Pregunta
____ query optimization takes place at execution time.
Respuesta
-
Automatic
-
Static
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Manual
-
Dynamic
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