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.pdfAn integrated collection of related data constitutes a *** database
In a typical library database system, integrity constraints would include which of the following rules? ***
II and III only
In SQL2, which of the following details can be provided when creating a database? *** I and III only
In SQL2, the default length of a bit string is *** 1
In SQL, a view is built with the command _____ and is deleted with the command _____. *** CREATE VIEW, DROP VIEW
In SQL, a semantic integrity constraint that involves specifying an action that is executed whenever a specified condition becomes true is known as a(n) *** trigger
In the SQL REVOKE command, the _____ clause can be used to specify that a granted privilege cannot be revoked if the privilege has been passed on to other users *** RESTRICT
In the Entity-Relationship (ER) model, objects that exist independently in the real world are modeled as
*** entities
In the context of databases, the entity on which a weak entity depends is known as a(n) *** identifying owner
In the context of databases, consider the relationship RESERVE<MEMBER,BOOK>, which indicates that a library member has reserved a book. If this relationship has a cardinality ratio of 1:N, which of the following is true? *** Members may reserve multiple books, but a book may be reserved by only a single member.
Consider a database table with the following functional dependencies.(FD1: A -> C)(FD2: {A, B} -> CIf both of these functional dependencies are true, then this table contains a _____ dependency.) ***
partial
Consider a database relation schema with three atomic attributes, A, B, and C that have the following functional dependencies. *** I and II only
Which of the following is (are) true regarding database tables? ***II only
In Entity-Relationship (ER) modeling, an entity is a _____, and a(n) _____ is a meaningful association between entities.*** uniquely identifiable object with independent existence, relationship
Which of the following statements about functional dependencies is (are) true? *** I, II, and III
A relational database schema is in First Normal Form if *** the domain of every attribute allows a single atomic value
Which of the following settings is needed for transactions in a banking database where simultaneous accesses to an account record may cause transactions to process inconsistent account balances? *** A stricter isolation level
Factors to consider when programming with transactions include which of the following? *** I and III only
Indexing a database table is likely to _____ performance of _____ queries on the table. *** impair, insert
Indexing a database table _____ improve(s) query performance when the table has _____ quantities of data.*** might not, small
Indexing a database table has the greatest effectiveness when *** column values are highly selective
For which of the following reasons is the relational model the most popular model for database systems? *** I and III only
In SQL, the _____ clause is used to filter out rows in a SELECT statement. *** WHERE
In SQL, which of the following clauses is (are) mandatory in a SELECT statement? *** III only
In two-phase locking protocols, a deadlock occurs when *** two or more transactions are blocked because each holds locks on resources that another transaction needs
Which of the following recovery actions is (are) required for ensuring the durability property of a database? *** II only 100%
When referring to the performance of a hard disk drive, once the read/write head is at the appropriate track, the amount of time it takes to position the appropriate disk block under the head is known as the
*** rotational latency
In hash files that use the linear probing scheme of conflict resolution, if a bucket is full when adding a new record, which if the following is true? *** A serial search is performed to find the first available slot in another bucket.
A data file is called fully inverted if *** each of its fields is associated with an index
Which of the following is (are) true regarding the arity of database tables? *** I, II, and III
The cardinality of an empty database table is *** 0
In database schemas, structural integrity constraints are imposed by the *** relational model
Which of the following relational algebra operations can be performed by a single SELECT statement in SQL? *** I, II, and III
In SQL, a scalar subquery returns *** a single column and a single row
In SQL CREATE TABLE statements, it can be specified that a column must always contain a valid value by using the _____ column specifier. *** NOT NULL
In embedded SQL, a statement that may be executed more than once can be dynamically built for later use with the _____ statement. *** PREPARE
If X and Y are attributes of a relation, X is functionally dependent on Y if *** each value of Y is associated with exactly one value of X
A table that contains one or more repeating groups is said to be in *** Unnormalized Form
In a relation R where X, Y, and Z are attributes, if X is functionally dependent on Y and Y is functionally dependent on Z, then *** X is transitively dependent on Z
In a recoverable schedule, if transaction S reads a data item previously written by transaction T, then the
*** commit operation of T must precede the commit operation of S
If a transaction has a(n) _____ lock on a data item, it can _____ the item. *** shared, read but not update
Types of file organizations in which records are store in no particular order include which of the following? *** II only
The technique of extendible hashing is a type of *** dynamic hashing
A data file can have *** at most one primary index or one clustering index
In Entity-Relationship (ER) modeling, an entity type that is existence-dependent on some other entity type is known as a *** weak entity type
In Entity-Relationship (ER) modeling, the multiplicity of a relationship is the *** number of possible occurrences of an entity type that may relate to an associated entity type in the relationship
A cluster index is an index defined on a(n ) _____ field. *** ordering
A collision occurs in hashing when the bucket in which the record to be _____ *** stored is full
A database is needed for which of the following application scenarios? *** I and II only
A deadlock occurs when *** 2 or more transactions wait indefinitely because each holds the data items of another
A deletion operation will _____ if the deletion leads to the violation of a referential integrity constraint.
*** fail
A difference operation can be applied to tables that *** are union compatible
A horizontal view allows users access to *** only specific rows of the defining tables
A livelock occurs when *** a transaction is aborted and restarted repeatedly
A relational schema is in first normal form, if the domain of all of its *** attributes can take on only atomic values
A shared lock on a data item represents permission to perform which of the operations, read and write, on the data item? *** Read only
A star schema in a data warehouse context refers to which of the following? *** A central fact table and a number of dimension tables
A vertical view allows users access to *** only specific columns of the defining tables
A weak entity type implies a *** relationship with total participation constraint
All changes made by a committed transaction can be recovered *** only if there have been no software failures
An E-Commerce database contains data about customers, products, orders, system response times, etc. Which of the following can be specified as integrity constraints in an E-Commerce database system? ***
I and III only
An E-Commerce system consists of the following components. Which of the same components must be included in a database management system? *** II only
An E-Commerce system consists of the following components. Which of these same components must be included in a database? *** I only
An E-Commerce system consists of the following components. Which of these same components will constitute a database system? *** I, II, and III
An exclusive lock on a data item represents permission to perform which of the operations, read and write, on the data item? *** Both read and write
An index file is usually used to index ______ of the data file. *** one field
An insertion operation will _____ if the inserted primary key has a NULL value. *** fail
An insertion operation will _____ if the insertion violates the uniqueness property of a key. *** fail
Consider a table with atomic attributes A, B, and C and the following functional dependencies. *** I and II only
Consider the following functional dependency. {A, B} -> {C} Regarding this dependency, which of the following statements is (are) true? *** None
Database design typically consists of which of the following phases? *** I, II, and III
DDL is used to *** specify the structure of a database
DML is used to *** add/modify/delete data in the database
During recovery, in which of the following ways are the before and after images used by the undo and redo actions? *** I and III only
For a relation to be in 2NF, _____ attribute must be fully functionally dependent on _____. *** every non-primary-key, the primary key
For a relation to be in 3NF, it should not contain _____ attribute that is transitively dependent on _____.
*** a non-primary key, the primary key
For two tables to be union compatible, corresponding columns from each table should have which of the following? *** the same domain
For two tables to be union compatible, the tables should be the same with respect to which of the following? *** degree
Force propagation policy _____ redo actions, and no-force propagation policy _____ redo actions. ***
does not require, requires
How does linear probing solve the problem of collisions in hashing? *** A serial search is performed from the point of collision to find the first available slot.
If X -> Y, which of the following would make Y fully dependent on X? *** X is a single attribute
Immediate update policy _____ undo actions, and deferred update policy _____ undo actions. ***
requires, does not require
In a hierarchical database, a single tree can accommodate which of the following types of binary relationships? *** I and II only
In a hierarchical database, data records are represented using which of the following data structures?
*** Trees
In a network database, a binary one-to-many relationship is typically represented using a *** linked list
In a network database, data records are represented using which of the following data structures? ***
Graphs
In a network database, the first record of an ordered linked list that represents a one-to-many relationship is called a(n ) *** owner
In a transaction, a ROLLBACK is used to *** discard all the updates (including inserts, deletes, modifications) of a transaction from the database
In a transaction, COMMIT specifies that *** all updates (including inserts, deletes, modifications) of a transaction are to be made permanent in the database
In a two-phase locking protocol, a transaction _____ downgrade a write lock to a read lock _____ ***
cannot, under any circumstances
In a two-phase locking protocol, what happens during the growing phase? *** The transaction can acquire locks, but cannot release its locks.
In a two-phase locking protocol, what happens during the shrinking phase? *** The transaction cannot acquire locks, but can release its locks.
In an ER model, a derived attribute is one whose values *** can be derived from the values of some other attributes
In an ER model, the cardinality ratio of a relationship type is *** the number of relationships of that relationship type in which an entity can participate
In an ER model, what is a recursive relationship type? *** The type of relationship between entities of one entity type
In an ER model, which of the following is true about a component attribute? *** A component attribute can be a composite attribute
In an ER model, which of the following is true about a composite attribute? *** A composite attribute can be broken into more basic attributes
In an Object-Relational model, which of the following data types are supported? *** I and II only
In contrast to _____ tables, a view refers to _____ *** base, a virtual table
In EER modeling, generalization is the process of generating *** superclasses out of subclasses In EER modeling, specialization is the process of generating *** subclasses out of superclasses In SQL, a database can be created by which of the following? *** the command CREATE SCHEMA
In SQL, a database can be destroyed by which of the following? *** the command DROP SCHEMA
In SQL, one function of the AS operator is to *** customize the names of columns in a query’s result
In SQL, the results of a _____ statement can be used to process a _____ statement *** SELECT, INSERT
In SQL, when destroying a database, the CASCADE option removes *** everything in the specified database: the data, schema, etc.
In SQL, when destroying a database, the RESTRICT option removes *** the schema if the database has no data (empty tables)
In SQL, which of the following clauses can be used to sort results in ascending or descending order of attribute values? *** ORDER BY
In SQL, which of the following operators are used to check for set membership in a SELECT statement?
*** IN and NOT IN
In SQL3, inheritance is specified using which of the following keywords? *** UNDER
In the Entity-Relationship model, a derived attribute is one *** whose value can be computed from the values of other attributes
In the Entity-Relationship model, properties that characterize entities and relationships are modeled as
*** attributes
In the Entity-Relationship model, the degree of a relationship specifies which of the following? *** The number of entities that participate in the relationship
In the relational model, which of the following is true about the data type of a column? *** It must be atomic and it cannot be an abstract data type
Small, highly focused databases at the departmental level that are used to build enterprise-wide data warehouses are known as **** data marts
Spatial data is _____-dimensional data. ***** multi
The arity of a table is the number of _____ in the table. ***** columns
The cardinality of a table is the number of _____ in the table. **** rows
The degree of a table is the number of _____ in the table. **** columns
The FD X -> Y is a full dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. **** no, removed from
The FD X -> Y is a partial dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. ***** at least one, removed from
The foreign key in a table T1 _____ the same _____ as the corresponding primary key in table T2.must have, name need not have, name must have, domain **** II and III
The functional dependency X -> Y is true if **** a value of X uniquely determines a value of Y
The physical storage structure will be _____ to the application programmer in a database approach, and will be _____ to the application programmer in a file system approach. **** hidden, visible
The result of a set difference operation r - s will be **** those tuples that are in r but not in s
The SQL clause to perform a set difference operation is ***** EXCEPT
The SQL clause to perform a set UNION operation is ***** UNION
The SQL keyword _____ makes the modifications of the transaction permanent, while the SQL keyword
_____ discards the modifications of the transaction. **** COMMIT, ROLLBACK
The strict two-phase locking protocol is _____ to implement ***** the easiest two-phase locking protocol
The term physical data independence refers to the ability to change ***** the physical layout of the data without changing the external schemas, the conceptual schemas, or the application programs
The term query by example refers to **** a visual query language developed by IBM
The undo action undoes the effects of a(n ) _____ transaction, and the redo action redoes the effects of a(n ) _____ transaction. ***** aborted, committed
Through normalization, data redundancy **** can be eliminated
Through normalization, update anomalies ***** can be eliminated
To retrieve data from a hierarchical database, program logic for performing _____ must be available.
**** navigation
What attributes does a subclass have? **** All the attributes of its superclass, and possibly more
What can be specified in the selection condition of a SELECT statement? **** a Boolean operation
What does a projection operation do? **** It selects columns from a table
What information is necessary when specifying the structure of a table? **** the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes
What is a drill-down operation in a data warehouse application? **** Deriving a fine-grained view, i.e., a disaggregated view along a particular dimension
What is a roll-up operation in a data warehouse application? **** Deriving a coarse-grained view, i.e., a summarized view along a particular dimension
What is an alternate key? **** Any key that is not a primary key
What is an identifying owner in an ER model? **** The entity upon which a weak entity's existence depends
When a string whose length is strictly less than n is entered as the value of a field whose SQL data type is CHAR(n ), the system responds by **** storing the string as is.
When is embedded SQL referred to as dynamic SQL? ***** when the embedded SQL is translated into DBMS calls at run-time
When is embedded SQL referred to as static SQL? ***** when the embedded SQL is translated into DBMS calls at compile-time
When mapping from an ER model to a relational model, a strong entity is mapped into a **** table
When removing a table from the schema, using the CASCADE option would ***** remove the table and all references to it
When removing a table from the schema, using the RESTRICT option would ***** remove the table if there are no references to it
When specifying a selection criterion in SQL, attributes can be renamed with which of the following operators? ***** AS
Which concurrency control protocols perform best in all situations? **** none
Which of the following are valid operations performed on spatial data? **** I and II only
Which of the following collections allows duplicate elements? **** II and III only
Which of the following commands can be used to give access permissions to a table? **** GRANT
Which of the following commands can be used to remove access privileges associated with a table?
***** REVOKE
Which of the following data models currently have the predominant market share ***** relational
Which of the following is a property (are properties) exhibited by good relational schemas? **** III only
Which of the following is an ordered collection? ***** II only
Which of the following is the predominant data type that is encountered in OLAP databases? ****
multi-dimensional
Which of the following is true about attributes in a relational model? Attributes can be multi-valued. Attributes can be composite. **** Neither I nor II
Which of the following is true about compensating transactions? **** The DBMS cannot automatically write compensating transactions
Which of the following is true about primary keys and foreign keys holding NULL value? **** A primary key cannot hold a NULL value and a foreign key can hold a NULL value
Which of the following is true about storage for derived attributes? **** Derived attributes are usually not stored because they can be computed
Which of the following is true about the effects of a transaction as seen by an external user who does not participate in the transaction? **** Transactions either complete, committing all changes to the DBMS, or rollback, resetting the DBMS to a state just prior to a transaction's execution
Which of the following is true about the growing phase and the shrinking phase of a strict two-phase locking protocol? *** The growing phase ends just before commit
Which of the following is true about the number of primary keys and alternate keys with respect to a table? **** here can be only one primary key, but many alternate keys
Which of the following is true about the physical storage of tables defined by views? ***** There is no extra physical storage needed to store tables that a view defines
Which of the following is true about the support for inheritance in Object-Relational models? **** Both single inheritance and multiple inheritance are supported
Which of the following is true about transactions affecting the consistency of a database? *** A transaction always leaves the database in a consistent state
Which of the following is true about updateability of views **** A view is not updateable if it involves aggregate functions and nested queries
Which of the following is true about views being up to date? **** Views are always up to date
Which of the following is true regarding database tables? *** A value may appear multiple times in a column
Which of the following problems can be caused by data redundancy in a relational schema? **** I, II, and III
Which of the following referentially triggered actions are supported in SQL when a referential integrity constraint is violated? SET NULL REJECT CASCADE SET DEFAULT **** I, III, and IV only
Which of the following SQL commands can be used to change, add, or drop column definitions from a table? *** ALTER TABLE
Which of the following SQL commands can be used to destroy and remove a table from the schema?
**** DROP TABLE
Which of the following SQL statements can be used to add a row to a table? **** INSERT
Which of the following SQL statements can be used to create a relational table? *** CREATE
Which of the following SQL statements can be used to modify just one row (out of many rows) in a table? UPDATE
Which of the following SQL statements can be used to remove a row from a table? **** DELETE
Which of the following statements concerning normal forms is true? **** A relation that is in second normal form is also in first normal form
Which of the following statements is (are) typically true of hierarchical databases? **** I and II
Which of the following types of databases store data in tables and represent relationships using foreign keys? ***** Relational databases
Which of the following will a good hash function do? **** spread keys around the file as evenly as possible
Who can always give access permissions to a table? ***** the owner of the table
With Query By Example, a user enters a query by **** filling in skeleton tables of the database with examples of what is to be retrieved
With respect to a relational table, what is a key? **** A minimal subset of columns that uniquely identifies a row in the table
Y is transitively dependent on X, if **** (a) X -> A, B and A -> Y