DBW301 - Random 525 part 2
# the term metadata refers to
"data about data"
# 5. In table, there is only one
- index clustered
#Q20 Which of the following is not a characteristic of the OLTP system compares to data warehouse system
. Unpredictable reporting
# Which statement is not correct to derive relations from superclass/subclass relationship?
... optimal and disjoint: Many relations will be created, one relation ....
# What is the estimated cardinality of the following operations on tables T(a,b), S(a,c). T has 100000 rows, 10000 different values in column a, 5000 in column b, table S has 2000 rows, 100 different values in a, 20 in column c: sel (a=10)(T)
10
# What is the estimated cardinality of the following operations on tables T(a,b), S(a,c). T has 100000 rows, 10000 different values in column a, 5000 in column b, table S has 2000 rows, 100 different values in a, 20 in column c: (sel (c=1)(T join S)
1000
# Suppose Staff entity has generalization/specialization relationship with three entities Manager, SalePersonnel and Secretary. The constraints on this generalization/specialization relationship is {Optional,And}. How many relation should be derived form this ERD, choose the most correct answer
2
# Suppose Staff entity has generalization/specialization relationship with three entities Manager, SalePersonnel and Secretary. The constraints on this generalization/specialization relationship is should be derived from this ERD, choose the most correct answer
3
# Suppose Staff entity has generalization/specialization relationship with three entities Manager, SalePersonnel and Secretary. The constraints on this generalization/specialization relationship is {Optional, OR}. how many relation should be derived from this ERD, choose the most correct answer
3
# Let R be a table with B(R) blocks on disk. B(R) <= M*(M-1), where M is the number of blocks of main memory which can be used for sorting, aggregation, join operations etc. What is the cost estimated cost of a merge sort in terms of block accesses
3*B(R)
# Given tables R(a,b), S(a,c). What is the estimated cardinality of the following operation assumed table R has 100000 rows, 100000 different values in column a primary keys, 500 in column b, table S has 2000 rows, 500 different values in a, 1000 in column c. sel(b=3)(R join S)
4
# What percentage of the total distribution is 3 sigma from the mean equal to?
99.73%
# _________, if fits into memory, costs only one disk I/O access to locate a record by given key.
A Dense Index
# Distributed processing is
A centralized database that can be accessed over a computer network
# If the isolation level is Repeatable Read
A phantom record may occur (e.g. after insertion)
# Choose the correct statement
A relation in which the intersection of each row and column contains one and only one value is in 1NF
# Choose the correct statement?
A relation in which the intersection of each row and column contains one and only one value is in 1NF
# Choose the most correct statement
A relation in which the intersection of each row and column contains one and only one value is in 1NF
# The online transaction processing applications support the day-to-day operations of an enterprise
A. False
# Data integrity characteristic of strategic information means
A. Information must be accurate and must conform to business rules
# Benefits from a data warehouse accrue only after the users put it to full use
A. True
# Fact tables generally occupy the most of the storage capacity
A. True
# Operational systems are online transaction processing (OLTP) systems
A. True
# ________ table contains the values we want to analyze
A. dimension
# The _______ diagrams crystallize the information requirements for the data warehouse
A. information package
# Which are Not the desired characteristics of strategic information
A. none of the others
#QN=37 A distributed database is which of the following?
Aa. A single logical database that is spread to multiple locations and is interconnected by a networ
#QN=101 If a denormalization situation exists with a one-to-one binary relationship, which of the following is true?
Aa. All fields are stored in one relation
#QN=180 Which of the following are the five built-in functions provided by SQL?
Aa. COUNT, SUM, AVG, MAX, MIN
#QN=175 Which of the following is valid SQL for an Index?
Aa. CREATE INDEX ID;
#QN=60 The SQL statement to create a view is:
Aa. CREATE VIEW
#QN=92 Which of the following modifications may not succeed?
Aa. Changing a column data type from char to dat
#QN=159 Transient data is which of the following?
Aa. Data in which changes to existing records cause the previous version of the records to be eliminated
#QN=43 Which of the following refers to something that can be identified in the users' work environment, something that the users want to track?
Aa. Entit
#QN=113 Hashing algorithm converts a primary key value into a record address.
Aa. False
#QN=115 A bitmap index is an index on columns from two or more tables that come from the same domain of values.
Aa. False
#QN=227 If no multivalued attributes exist in a relation, then the relation is in what normal form?
Aa. First normal form
#QN=31 Which of the following products implemented the CODASYL DBTG model?
Aa. IDM
#QN=6 Which of the following is a group of one or more attributes that uniquely identifies a row?
Aa. Key
#QN=176 The SQL keyword(s) ________ is used with wildcards.
Aa. LIKE only
#QN=141 Which constraint requires that the binary relationship indicate all combinations that must appear in the ternary relationship?
Aa. MUST COVE
#QN=42 Which of the following indicates the minimum number of entities that must be involved in a relationship?
Aa. Minimum cardinalit
#QN=128 Which of the following column properties specifies whether or not cells in a column must contain a data value?
Aa. Null statu
#QN=117 The fastest read/write time and most efficient data storage of any disk array type is:
Aa. RAID-0
#QN=195 The SQL statement that queries or reads data from a table is ________ .
Aa. SELEC
#QN=177 Which of the following is the correct order of keywords for SQL SELECT statements?
Aa. SELECT, FROM, WHER
#QN=7 Precedence graphs help to find a
Aa. Serializable schedule
#QN=27 SQL stands for ________ .
Aa. Structured Query Languag
#QN=13 Which type of entity is related to two or more associated entities that each contain specialized attributes that apply to some but not all of the instances of the entity?
Aa. Supertype entity
#QN=162 An autonomous homogenous environment is which of the following?
Aa. The same DBMS is at each node and each DBMS works independently
#QN=234 When mapping a supertype/subtype relationship which of the following is true?
Aa. The supertype primary key is assigned to each subtype
#QN=198 Which of the following is true concerning an ODBMS?
Aa. They have the ability to store complex data types on the Web
#QN=199 The reserved word enum is used for which of the following?
Aa. To define a range for an attribute
#QN=133 A goal of data mining includes which of the following?
Aa. To explain some observed event or condition
#QN=111 The use of the double NOT EXISTS can be used to find rows that do not match some specified condition.
Aa. Tru
#QN=117 Reverse engineering is the process of reading a database schema and producing a data model from that schema.
Aa. Tru
#QN=122 Adding null columns to a table is straightforward.
Aa. Tru
#QN=146 A foreign key is used to implement relationships between tables.
Aa. Tru
#QN=153 Intersection tables are ID-dependent on both their parent tables.
Aa. Tru
#QN=160 When the child entity is required, we are restricted from creating a new parent row without also creating a corresponding child row at the same time.
Aa. Tru
#QN=162 When the parent entity is required and the parent has a surrogate key, update actions can be ignored.
Aa. Tru
#QN=163 When the parent entity is required, a new parent row can always be inserted.
Aa. Tru
#QN=164 For every relationship, there are six possible referential integrity actions.
Aa. Tru
#QN=165 An ideal primary key is short, numeric and seldom changing.
Aa. Tru
#QN=136 A data mart is designed to optimize the performance for well-defined and predicable uses.
Aa. True
#QN=137 Successful data warehousing requires that a formal program in total quality management (TQM) be implemented.
Aa. True
#QN=138 Data in operational systems are typically fragmented and inconsistent.
Aa. True
#QN=140 Independent data marts are often created because an organization focuses on a series of short-term business objectives.
Aa. True
#QN=154 Every key used to join the fact table with a dimensional table should be a surrogate key
Aa. True
#QN=172 Each site (or node) in a distributed system is subject to the same types of failure as in a centralized system.
Aa. True
#QN=174 Synchronization for pull replication is less disruptive and occurs only when needed by each site, not when a central master site thinks it is best to update.
Aa. True
#QN=177 An increasingly popular option for data distribution as well as for fault tolerance of any database is to store a separate copy of the database at each of two or more sites.
Aa. True
#QN=181 Data replication is favored where most process requests are read-only and where the data are relatively static
Aa. True
#QN=182 The cost to perform a snapshot refresh may depend on whether the snapshot is simple or complex
Aa. True
#QN=183 The semijoin approach saves network traffic.
Aa. True
#QN=207 The ODMG Object Model requires that a relationship be specified in both directions
Aa. True
#QN=210 The ODMG Object Model supports only unary and binary relationships
Aa. True
#QN=213 An attribute's value is either a literal or an object identifier
Aa. True
#QN=218 Specifying a key ensures that no two objects belonging to a class have the same value for the key attribute(s).
Aa. True
#QN=220 In ODL, you specify an operation using parentheses after its name
Aa. True
#QN=242 In a 1:M relationship, the primary key on the one side migrates to the many side to become the foreign key on the many side.
Aa. True
#QN=244 A null value is assigned when no other value applies.
Aa. True
#QN=248 A candidate key must uniquely identify each row.
Aa. True
#QN=33 Oracle maintains a System Change Number (SCN) which is a database-wide value that is incremented by Oracle whenever database changes are made.
Aa. True
#QN=40 The purpose of timestamping is to avoid the use of locks.
Aa. True
#QN=8 Two basic constructs to link one piece of data with another piece of data: sequential storage and pointers.
Aa. True
#QN=103 What is the best data type definition for Oracle when a field is alphanumeric and has a length that can vary?
Aa. VARCHAR2
#QN=38 Which type of entity cannot exist in the database unless another type of entity also exists in the database, but does not require that the identifier of that other entity be included as part of its own identifier?
Aa. Weak entit
#QN=132 A foreign key is:
Aa. a column containing the primary key of another table
#QN=97 Changing cardinalities in a database is:
Aa. a common database design task
#QN=181 In an SQL SELECT statement querying a single table, according to the SQL-92 standard the asterisk (*) means that:
Aa. all columns of the table are to be returned
#QN=96 The EXISTS keyword will be true if:
Aa. any row in the subquery meets the condition only
#QN=87 A transaction in which either all of the database actions occur or none of them do is called:
Aa. atomic
#QN=70 The SQL ALTER statement can be used to:
Aa. change the table structure
#QN=103 A tool that can help designers understand the dependencies of database structures is a:
Aa. dependency graph
#QN=134 In a 1:1 relationship, the foreign key is placed in:
Aa. either table without specifying parent and child tables
#QN=196 The SQL keyword BETWEEN is used:
Aa. for ranges
#QN=95 Locks placed by the DBMS are called ________ .
Aa. implicit lock
#QN=41 A recursive relationship is a relationship between an entity and ________ .
Aa. itsel
#QN=221 The entity integrity rule states that:
Aa. no primary key attribute may be null
#QN=39 In a one-to-many relationship, the entity that is on the one side of the relationship is called a(n) ________ entity.
Aa. paren
#QN=11 In a one-to-many relationship, the entity that is on the one side of the relationship is called a(n) ________ entity
Aa. parent
#QN=24 An application where only one user accesses the database at a given time is an example of a(n) ________ .
Aa. single-user database applicatio
#QN=81 The advantage of optimistic locking is that:
Aa. the lock is obtained only after the transaction has processed
#QN=144 If a relationship has a cascade updates constraint, then if ________ in the parent table is changed, then the same change will automatically be made to any corresponding foreign key value.
Aa. the primary ke
#QN=193 To define what columns should be displayed in an SQL SELECT statement:
Aa. use FROM to name the source table(s) and list the columns to be shown after SELECT
# Which one should not use when choosing an index
Add secondary index to an attribute if the query will retrieve a significant propotion of the relation
# In a fact table, there are 3 kinds of attributes
All the others
# In a fact table, there are 3 kinds of attributes:
All the others
# Data Warehouse provides the best support for analysis while OLAP carries out the _________ task
Analysis
# Which on is not basic concept of the Entity Relationship (ER) model
Attribute type
# Which one is not basic concept of the Entity Relationship (ER) model?
Attribute type
# ________ indicator of high-quality data ensures the form and content of a data field is the same across multiple source systems
B. Consistency
# What are the three major areas in the data warehouse
B. Data acquisition, data storage, information delivery
# In the data warehouse architecture, _________ sits on top of all the other components. It coordinates the services and activities
B. Management and control component
# The _______ model contains the structures and relationships represented in the data schema coded with data definition language (DDL) of the DBMS
B. Physical
# OLAP systems privide ______ and roll-up capabilities
B. drill-down
# Bitmapped indexes are ideally suitable for _______ data
B. low-cardinality
# which statement is correct?
B. the primary key of the fact table consists of the primary keys of all the connected dimensions
# The requirement of the data warehouse DBMS are all of the following, excepts
Basic query function
#QN=225 A transitive dependency is which of the following?
Bb. A functional dependency between two or more nonkey attributes
#QN=156 The load and index is which of the following?
Bb. A process to load the data in the data warehouse and to create the necessary indexes
#QN=134 An operational system is which of the following?
Bb. A system that is used to run the business in real time and is based on current data
#QN=104 If a denormalization situation exists with a many-to-many or associative binary relationship, which of the following is true?
Bb. All fields are stored in two relations
#QN=110 What is the best data type definition for Oracle when a field is alphanumeric and has a fixed length?
Bb. CHAR
#QN=157 The extract process is which of the following?
Bb. Capturing a subset of the data contained in various operational system
#QN=145 Reconciled data is which of the following?
Bb. Current data intended to be the single source for all decision support system
#QN=187 SQL query and modification commands make up a(n) ________ .
Bb. DM
#QN=172 The command to eliminate a table from a database is:
Bb. DROP TABLE CUSTOMER
#QN=173 ON UPDATE CASCADE ensures which of the following?
Bb. Data Integrity
#QN=130 Which of the following column properties would be used to specify that cells in a column must contain a monetary value?
Bb. Data typ
#QN=109 Database redesign is especially difficult if the database has no data.
Bb. Fals
#QN=114 The data model produced from the reverse engineering process does not include intersection table data.
Bb. Fals
#QN=116 The SQL-92 command to change a table name is RENAME TABLE.
Bb. Fals
#QN=118 The data model produced from the reverse engineering process is a true logical model.
Bb. Fals
#QN=148 In 1:N relationships, which entity becomes the parent entity is arbitrary.
Bb. Fals
#QN=151 When the parent entity is required, a new child row can always be inserted.
Bb. Fals
#QN=161 (STREET ADDRESS, CITY, STATE, ZIP) is an ideal primary key.
Bb. Fals
#QN=128 Data-volume and frequency-of-use statistics are not critical inputs to the physical database design process
Bb. False
#QN=146 Joining is the process of partitioning data according to predefined criteria.
Bb. False
#QN=155 Every key used to join the fact table with a dimensional table should be a surrogate key
Bb. False
#QN=176 Databases that are stored on computers at multiple locations and are not interconnected by a network are known as distributed databases.
Bb. False
#QN=206 ODL supports the abstract keyword for classes and operations.
Bb. False
#QN=239 Weak entities do not get mapped into a relation.
Bb. False
#QN=240 A primary key may be null.
Bb. False
#QN=245 The primary key in a relation does not need to be underlined.
Bb. False
#QN=249 Well-structured relations encourage anomalies of data.
Bb. False
#QN=39 Databases that are stored on computers at multiple locations and are not interconnected by a network are known as distributed databases.
Bb. False
#QN=223 If no multivalued attributes exist and no partial dependencies exist in a relation, then the relation is in what normal form?
Bb. First normal form
#QN=201 Which of the following is true concerning the following statement: class Manager extends Employee
Bb. Manager is a concrete class and a subclass
#QN=37 Which of the following indicates the maximum number of entities that can be involved in a relationship?
Bb. Maximum cardinalit
#QN=90 Which of the following allows dirty reads, nonrepeatable reads and phantom reads to occur?
Bb. Read uncommitte
#QN=99 The strictest transaction isolation level provided by SQL Server is called:
Bb. SERIALIZABLE
#QN=54 Which type of entity has its relationship to another entity determined by an attribute in that other entity called a discriminator?
Bb. Subtype entit
#QN=71 What SQL structure is used to limit column values of a table?
Bb. The CHECK constrain
#QN=109 Which of the following is not a factor to consider when switching from small to large block size?
Bb. The number of columns
#QN=35 A homogenous distributed database is which of the following?
Bb. The same DBMS is used at each location and data are distributed across all nodes
#QN=222 When mapping a many-to-many unary relationship into a relation which of the following is true?
Bb. Two relations are created
#QN=98 The NOT EXISTS keyword will be true if:
Bb. all rows in the subquery fail the condition
#QN=50 Entities of a given type are grouped into a(n):
Bb. entity class
#QN=75 Locks placed by command are called ________ .
Bb. explicit lock
#QN=13 For some relations, changing the data can have undesirable consequences called:
Bb. modification anomalies
#QN=32 An Enterprise Resource Planning application is an example of a(n) ________ .
Bb. multiuser database applicatio
#QN=183 The SQL -92 wildcards are ____ and ____ .
Bb. percent sign (%); underscore (_
#QN=105 Because of the importance of making data model changes correctly, many professionals are ________ about using an automated process for database redesign.
Bb. skeptica
#QN=142 Each entity is represented as a(n):
Bb. table
# The term BPR expands to __________.
Business Process Re-engineering
# Which of the following is not a phase in Cross Industry Standard Process for Data Mining (CRISP-DM) model?
Business preparation
# Which is(are) related to the time -variant nature of the data in a data warehouse
C. All the others
# In which case, indexes can improve the performance
C. Read data
# Which dimension does a data warehouse usually have
C. Time
# __________ acts as the glue that connects all parts of the data warehouse
C. metadata
# Which statement is not correct
Cardinality detemines whether all or only some entity occurences participate in a relationship
#QN=133 Which of the following columns is(are) are required in a table?
Cc. A primary ke
#QN=101 What SQL command will allow you to change the table STUDENT to add the constraint named GradeCheck that states that the values of the Grade column must be greater than 0?
Cc. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0)
#QN=87 What SQL command can be used to delete columns from a table?
Cc. ALTER TABLE TableName DROP COLUMN ColumnName
#QN=224 A foreign key is which of the following?
Cc. An attribute that serves as the primary key of another relation
#QN=137 Which of the following data constraints would be used to specify that the value of a cell in one column must be less than the value of a cell in another column in the same row of the same table?
Cc. An intrarelation constrain
#QN=55 Which type of entity represents a logical generalization whose actual occurrence is represented by a second, associated entity?
Cc. Archetype entit
#QN=86 Which of the following SQL statements are helpful in database redesign?
Cc. Both of the above are helpful
#QN=103 Which of the following is a way to create and modify tables using SQL Server?
Cc. Both of the two methods above will work
#QN=24 The metadata is created by the
Cc. DDL interpreter
#QN=167 The command to remove rows from a table 'CUSTOMER' is:
Cc. DELETE FROM CUSTOMER WHERE ..
#QN=184 To remove duplicate rows from the results of an SQL SELECT statement, the ________ qualifier specified must be included.
Cc. DISTINCT
#QN=91 Which of the following locks the item from access of any type?
Cc. Exclusive loc
#QN=4 A relation is in this form if it is in BCNF and has no multivalued dependencies:
Cc. Fourth normal form
#QN=102 Selecting a data type involves which of the following?
Cc. Improve data integrity
#QN=202 Which of the following is an ordered collection of elements of the same type?
Cc. List
#QN=49 In which of the following can many entity instances of one type be related to many entity instances of another type?
Cc. Many-to-Many Relationshi
#QN=192 To sort the results of a query use:
Cc. ORDER BY
#QN=187 A semijoin is which of the following?
Cc. Only the joining attributes are sent from one site to another and then only the required rows are returned
#QN=84 Which of the following disallows both dirty reads and nonrepeatable reads, but allows phantom reads?
Cc. Repeatable rea
#QN=36 Replication should be used when which of the following exist?
Cc. The application's data can be somewhat out-of-date
#QN=12 Which of the following is not a restriction for a table to be a relation?
Cc. The columns must be ordered
#QN=104 How many copies of the database schema are typically used in the redesign process?
Cc. Thre
#QN=230 When mapping a binary many-to-many relationship into a relation which of the following is true?
Cc. Three relations are created
#QN=19 SQL views can be used to hide:
Cc. both of the above can be hidden by an SQL view
#QN=59 SQL views can be used to hide:
Cc. both of the above can be hidden by an SQL view
#QN=88 Database redesign is not terribly difficult if the:
Cc. database has no data
#QN=197 A subquery in an SQL SELECT statement:
Cc. has a distinct form that cannot be duplicated by a join
#QN=92 The size of a lock is called:
Cc. lock granularity
#QN=136 The identifier of an entity will become the ________ of the new table.
Cc. primary ke
#QN=68 A reason for using an SQL view to hide columns is:
Cc. to accomplish both of the above
#QN=8 A relation is considered a:
Cc. two-dimensional table
# which one is a problem of the ER models
Chasm trap
# Which one is not a step in conceptual database design phase
Check model to add controlled redundancy
# Classification consists of examining the properties of a newly presented observation and assigning it to a predefined ____________.
Class
#Q16 Which one is not basic client-server architecture of an object-oriented database system
Class Server
# ________ is the technique in which existing heterogeneous segments are reshuffled, relocated into homogeneous segments
Clustering
#Q14 Which one is not a transformation rule for relation algebra operations to construct the query tree when doing query processing
Commutativity of projection and intersection
# All of the followings are query processing phases, excepts
Compilation
# Which one is not benefit of the database replication?
Connected computing
# Which one is not main benefit of the database replication?
Connected computing
# Which one is a problem of the ER model?
Connection trap
# What does lazy replication mean?
Copies are updated at some time in the future
# Which one is not a problem associated with data redundancy
Create anomalies
# All of the following result from quality audits EXCEPT
Creation of quality metrics
# See picture
D. sales
# Metadata in DW is similar___ to the
Data dictionary
# ____focus is on how managers view the business
Data warehouse
#Q21 Which statement is incorrect regards to database replication
Database vendor always provides either distributed DBMS or database replication
#QN=97 Using SQL Server 2000, which of the following symbols is used to indicate parameters in stored procedures?
Dd.
#QN=131 Data scrubbing is which of the following?
Dd. A process to upgrade the quality of data before it is moved into a data warehouse
#QN=95 What SQL command can be used to add columns to a table?
Dd. ALTER TABLE TableName ADD ColumnNam
#QN=160 A multifield transformation does which of the following?
Dd. All of the above
#QN=169 Which of the following is the original purpose of SQL?
Dd. All of the above
#QN=186 Which of the following do you need to consider when you make a table in SQL?
Dd. All of the above
#QN=189 A distributed database can use which of the following strategies?
Dd. All of the above
#QN=194 Using ODL, you can define which of the following?
Dd. All of the above
#QN=196 The object definition language (ODL) is which of the following?
Dd. All of the above
#QN=69 Which of the following is an SQL trigger supported by Oracle?
Dd. All of the above
#QN=64 For what purposes are views used?
Dd. All of the above are uses for SQL views
#QN=91 Before any changes to database structure are attempted one should first:
Dd. All of the above should be done
#QN=131 Which of the following situation requires the use of ID-dependent entities?
Dd. All of the above use ID dependent entitie
#QN=118 A rule of thumb for choosing indexes for a relational database includes which of the following?
Dd. Be careful indexing attributes that have null values
#QN=203 A relationship should be specified how in the ODL?
Dd. Both direction
#QN=56 The SQL command to create a table is:
Dd. CREATE TABLE
#QN=145 Which of the following column properties would be used to specify that cells in a column must contain a monetary value that is less than another monetary value in the same row?
Dd. Data constraint
#QN=83 Which of the following refers to a cursor type where changes of any type and from any source are visible?
Dd. Dynami
#QN=232 When mapping a ternary relationship with an associative entity into a relation which of the following is true?
Dd. Four relations are created
#QN=23 What is not an advantage of stored procedures?
Dd. Increased network traffic
#QN=36 The DBMS that is most difficult to use is ________ .
Dd. Oracle Corporation's Oracl
#QN=76 Which of the following locks the item from change but not from read?
Dd. Shared loc
#QN=104 With which type of SQL Server recovery model, is no logging done?
Dd. Simple recover
#QN=102 Which is not true of a correlated subquery?
Dd. They are very similar to a regular subquery
#QN=10 A functional dependency is a relationship between or among:
Dd. attributes
#QN=11 Table is synonymous with the term:
Dd. attributes
#QN=9 In the relational model, relationships between relations or tables are created by using:
Dd. foreign keys
# The users of data warehouse are knowledge workers in other words they are _________ in the organization
Decision maker
# Which one is not an additional semantic modelling concept in Enhanced Entity-Relationship (EER) model?
Decomposition
# If every key in the data file is represented in the index file then index is
Dense Index
# Which one is not a step in logical database design phase?
Derive relationships for logical data model
# Which one is a type of fragmentation?
Derived Horizontal
# A control chart helps the project manager:
Determine if a process is functioning within set limits
# All of the followings are data mining technique, excepts
Different time sequence discovery
# Which constraints used in specialization and generalization, choose two answers?
Disjoint + Participation
# Which statement is not correct about query processing?
Disk access tends not to be dominant cost in query processing for centralized DBMS
# ACCESSIBLE characteristic of strategic information means
Easily accessible with intuitive access paths, and responsive for analysis
# Which one is not benefit of storing methods in database in an object-oriented database system?
Easy to implement
# Which one is not basic concept of the Entity Relationship (ER) model?
Entity
# Which statememt is correct regarding to dimensional model?
Every fact table has at least one Foreign Key
#Q8 Which one is not a characteristic of the information extracting from database by using data mining tools
Expected
# The followings are characteristics of the information extracting from database by using data mining tools, excepts
Explicitly presented
# The followings are characteristics of the information extracting from database by using data mining tools, excepts
Explicity presented
# Suppose the amount of data recorded in an organization is doubled every year. This increase is __________.
Exponential
#Q23 Which one is not an alternative strategy for developing an OODBMS
Extending a relational DBMS with object-oriented capabilities
# Which one is not an alternative strategy for developing an OODBMS?
Extending an existing object-oriented programming language with database capabilities
# Source data in DW many come from
External data, production data, internal data, archived data
# WHich one is a problem of the ER models
Fan trap
# The advantage of hashing is
Fast computation of hash values from a key
# Back propagation neural network uses __________.
Feed-forward topology
# Which is NOT a characteristic of a data warehouse?
Few internal and external sources
# Why is dynamic block assignment (indirect mapping) of the DBS page address space to disk blocks is to prefer a static assignment
Flexibility of disk block assignment
# Which statement is not correct to derive relations for logical model?
For each strong entity in the data model, create a relation that includes all the simple attributes of that entity. Composite attributes will be ignored.
# A secondary index may be used
For evaluation of a foreign key relationship
# Which one is advantage of ORDBMSs compare to OODBMSs?
Gives rise to increased productivity both for developer and end-user
# Regarding to Online Analytical Processing (OLAP), which statement is INCORRECT?
Holds daily Latest Transactional Data related to your application
# Which one is not a step in conceptual database design phase?
Identify entity domains (types).
# Which statement is incorrect regards to serializability of the transactions?
If precedence graph contains cycle then schedule is conflict serializable
# Which statement is incorrect regards to the serializabity of the transactions?
If precedence graph contains cycle then...
# Which one is not basic rule of locking?
If transaction has shared lock on item, can both read and update item
# There are many variants of the traditional nested-loop join. If there is an index and that index is exploited, then it is called
Index nested-loop join
# The goal of __________ is to look at as few blocks as possible to find the matching records(s).
Indexing
# As OODBMS Manifesto which one of the followings is not be supported
Integrity
# Which constraint does not exist in specialization and generalization?
Joint
# _______ is an application of information and data
Knowledge
# Taken jointly, the extract programs or naturally evolving systems formed a spider web, also known as
Legacy Systems Architecture
# Suppose locking is used for synchronization of transactions. A lost update may occur if
Locks are set before accessing/ updating an object and released immediately after.
# Which one is an important property of the decomposition?
Lossless-join property
# The data warehouse is an informational enviroment that
Makes the enterprise's current and historical information easily available for strategic decision making
# Which one is not category of constraints of specialization and generalization?
Mandatory and joint
#Q1 Which statement is not correct about query processing?
Memory access tends to be dominant cost in query processing for centralized DBMS
# All of the followings are most common mechanisms for conflict detection and resolution, excepts
Most frequently update
# All of the followings are type of relationship excepts
Multi-sides
# All of the followings are type of relationships, excepts
Multi-sides
# Choose the incorrect statement about User-Defined Routines (URDs)?
Must be defined as part of a UDT
#Q11 Choose the incorrect statement about User-Defined Routines (UDRs)
Must be defined as part of a UDT
# What does the "WAL" mean?
Never write into the database before a log record has been written
#Q15 Which of the following is not a property of the data in a data warehouse
Non-summarized
# All of the followings are query processing phases, excepts
Normalization
# Which one is not typical stage of the query decomposition phase when doing query processing?
Normalization analysis
# Suppose in a relational schema for a library we have a table "Books" and the row of a book contains attributes of the student who lend the book, (E.G. Books(bNo, title, ..., studentNo, studentName, Tel, ...) What is wrong with the design?
Not in 3rd normal form
# In _________ system, the contents change with time
OLTP
# System capture detail of events or transactions
OLTP
# System focus on individual events
OLTP
# Entity-Relationship Modeling is suitable for __
OLTP systems
# Entity-Relationship Modeling is suitable for__
OLTP systems
# Choose the correct statement
ORDBMSs (Object Relational DBMSs) are RDBMSs with some OO features being added
# Which statement is incorrect regards to timestamping?
Older transactions, transactions with bigger timestamps, get priority in the event of conflict
# A dense index, if fits into memory, costs only ______ disk I/O access to locate a record by given key
One
# Which statement is incorrect
One relation can have both clustering index and primary index
# Choose the correct statement regards database replication?
One site can be both the master site and slave site for same replication group
# Which kind of relationship between entities does not necessarily need a separate table when represented in the relational model?
One-to-one
# A subject-oriented, current-valued, detailed database.
Operational data store
# Which one is not category of constraints of specialization and generalization?
Optional and joint
# Which is the correct sequence of query processing steps
Parsing - query rewrite - optimization - code generation - execution
# Which statement is not correct?
Participation describes maximum number of possible relationship occurrences for an entity participating in a given relationship type
# Which one is not a good heuristic rule that could be applied during query processing
Perform Selection operations as lately as possible
# Which one is not a good heuristic rule that could be applied during query processing?
Perform Selection operations as lately as possible
#Q22 Which one is not a good heuristic rule that could be applied during query processing
Perform Selection operations as lately as possible
# Which one is not an example of potential problems caused by concurrency?
Phantom read
# The classification technique can be use for which of the following data mining operations?
Predictive modeling
#Q25 Which of the following is not a reason for creating a data mart
Provide data in a form that matches the whole view of the data by many business application areas
# The data warehouse is an informational environment that
Provides an integrated and total view of the enterprise
# All of the following are examples of the cost of nonconformance EXCEPT:
Quality training
# The following histtory is executed in this order (without synchronization). r2(x) r1(y) w2(x) r1(x) c1 a2 (a2 means abort of TA2) This results in a
Read uncommitted
# Why is traversal of a non-clustered (B+-tree) index - leaf pages contain pointers to heap storage - expensive?
Records may be distrubuted over the persistent storage, needs block access for each key
#Q12 The advantage of the distributed DBMS is
Reflects organizational structure
# Which one is not a type of transaction in IBM's Distributed Relational Database Architecture (DRDA)?
Remote all of work
# What can a correctly defined trigger not be used for?
Sending an email after a deletion of a row of some table occurred
# All of the following are rules to construct the query tree when doing query processing, excepts
Sequence is directed from root to leaves
# What is not main architecture of parallel DBMS?
Shared processor
# Which of the following statements about a bitmap index for attributes of some table R is wrong?
Should only be used if s has a large number of values
# All of the followings are type of attribute, excepts
Single Attribute
# Which one is not a kind of key in a relation?
Single key
# (1 hinh, 1 mat mau xanh) which operation is illustrated in the figure
Slice
# (2 hinh, 1 mat mau xanh) which operation is illustrated in the figure
Slice
# Regarding to data warehouse. Which statement is true
Some indexes are specified all the design time, and some others are added at maintenance time
# Concurrent execution of 2 transactions with isolation level "read uncommitted" will
Sometimes results in an inconsistent DB state
# __ signifies that the data warehouse stores the information around a particular subject such as product, customer, sales etc
Subject oriented
# Which of the following is NOT part of the disk access time?
Surface torsion time
# Testing the entire population would:
Take too long
# There are many variants of the traditional nested-loop join. If the index is built as part of the query plan and subsequently dropped, it is called
Temporary index nested-loop join
# Which statement is correct?
The RD is more complex than the ERD causes of the RD contains some foreign keys that associate some relations
# Which statement is incorrect regards to the transaction
The consistency must not be violated during transaction
# Which parameter is not relevant for calculating the height of a B+-tree index?
The data type of the attributes of the records which are not keys
# Quality is:
The degree to which the project meets requirements
# Which statement is not correct to derive relations from 1:1 binary relationship?
The participation constraints are used to decide whether it is best to represent the relationship by combining the entities involved into one relation or by creating two relations
# The coordinator of a distrubuted transaction crashes after sending the decision (commit/abort) to the resource managers and after having received one of the acknowledgements from the resource managers (more than one). What will happen?
The resource managers which did not get the decision are blocked
# What is Business intelligence
The systems and technologies for gathering, cleansing, consolidating, and storing corporate data. The tools, techniques, and applications for analyzing the stored data
# In SQL (Structured Query Language), which statement(s) is (are) TRUE regarding to the term cardinality? 1) Low-cardinality refers to columns with few unique values. 2) The lower the cardinality, the less duplicated elements in a column. 3) SQL databases use cardinality to help determine the optimal query plan for a given query
There isn't statement
# Which of the following is a property of the data in a data warehouse?
Time-variant
# Which statement is incorrect regards to the Concurrency Control Techniques
Timestamping is a conservative method
# Which statement is incorrect regards to the Concurrency Control Techniques?
Timestamping is a optimistic method
# Which statement is correct
Timestamping shedule is view serializable
# Which statement is incorrect regards to the database recovery?
Transaction manager responsible for atomicity and durability
# Which of the following is not a characteristic of the OLTP system compares to data warehouse system?
Unpredictable reporting
# Which does NOT describe a data warehouse
Updateable
# Choose the correct statement?
Vertical fragmentation defined using projection operation of relational algebra
# Which statement is incorrect regards to the serializability of the transactions
View serializable shedule may contain one or more blind writes
# When does a transaction T using snapshot isolation (MVCC) read a version which was committed after the begin but before the end of T?
When no other transaction has written x and committed during the lifetime of T
# Which statement is correct
With OLAP cube, we are able to create data mining structure on this data which can be helpful in forecasting, prediction
# B-Tree is used as an index to provide access to records
Without scanning the entire table
#QN=55 The normal form that is not necessarily dependency preserving is
aa. 2NF
#QN=79 What will be the number of columns and rows respectively obtained for the operation, A - B, if A B are Base union compatible and all the rows of a are common to B? Assume A has 4 columns and 10 rows; and B has 4 columns and 15 rows
aa. 4,0
#QN=84 Relationships among relationships can be represented in an-E-R model using
aa. Aggregation
#QN=94 Dependency preservation is not guaranteed in
aa. BCNF
#QN=66 Manager salary details are hidden from the employee .This is
aa. Conceptual level data hiding
#QN=62 The FD A ? B , DB ? C implies
aa. DA ? C
#QN=65 Relations produced from an E-R model will always be
aa. First normal form
#QN=67 Which of the following is true for network structure?
aa. It is a physical representation of the data
#QN=17 The operation which is not considered a basic operation of relational algebra is
aa. Join
#QN=100 operator is used to compare a value to a list of literals values that have been specified
aa. Like
#QN=4 Checkpoints are a part of
aa. Recovery measures
#QN=8 The rule that a value of a foreign key must appear as a value of some specific table is called a
aa. Referential constrain
#QN=16 In an E-R diagram double lines indicate
aa. Total participation
#QN=30 Shadow paging has
aa. no redo
#QN=26 When R ? S ? ? , then the cost of computing R S is
aa. the same as R x S
#QN=56 A functional dependency of the form x ? y is trivial if
aa. y ? x
# __ right value for that occurrence of the data element
accuracy
# right value for that occurrence of the data element
accuracy
# which one should use when choosing an index
add secondary index to any attribute or relation that is frequently updated
# which one is not overheat involved in maintenance and use of secondary indexes
adding and index record to every secondary index whenever tuple is retrieved
#QN=13 A relation is in _________ if an attribute of a composite key is dependent on an attribute of other composite key.
bb. 3NF
#QN=15 What are the desirable properties of a decomposition?
bb. Dependency preservation
#QN=14 What is data integrity?
bb. It is the data contained in database that is accurate and consistent
#QN=6 The language that requires a user to specify the data to be retrieved without specifying exactly how to get it is
bb. Non-Procedural DM
#QN=9 The clause in SQL that specifies that the query result should be sorted in ascending or descending order based on the values of one or more columns is
bb. Order b
#QN=51 The cost of reading and writing temporary files while evaluating a query can be reduced by
bb. Pipelining
#QN=59 Which of the following is not a characteristic of a relational database model?
bb. Tree like structure
#QN=22 Which of the following is not a consequence of concurrent operations?
bb. Update anomaly
#QN=25 When an E-R diagram is mapped to tables, the representation is redundant for
bb. weak relationship sets
# Select the correct comment on the two statement bellow 1) when you perform the logical design of the database, your goal is to produce a conceptual model that reflects the information content of the real-world situation 2) In physical design, you are getting closer to the operating systems, the database software, the hardware, and the computing platform.
both statement are correct
#QN=78 If both the functional dependencies : X?Y and Y?X hold for two attributes X and Y then the relationship between X and Y is
cc. 1:1
#QN=3 Relational Algebra does not have
cc. Aggregation operators
#QN=52 A transaction is in state after the final statement has been executed.
cc. Committed
#QN=99 Isolation of the transactions is ensured by
cc. Concurrency control
#QN=32 DROP is a statement in SQL
cc. DDL
#QN=68 Which two files are used during operation of the DBMS?
cc. Data dictionary and transaction log
#QN=75 The values of the attribute describes a particular
cc. Entity instance
#QN=5 Tree structures are used to store data in
cc. Hierarchical model
#QN=18 Fifth Normal form is concerned with
cc. Join dependency
#QN=37 In an E-R, Y is the dominant entity and X is a subordinate entity. Then which of the following is incorrect
cc. Operationally, if X is deleted, so is Y
#QN=63 The graphical representation of a query is
cc. Query Tree
#QN=96 Which of the following constitutes a basic set of operations for manipulating relational data?
cc. Relational algebra
#QN=34 The keyword to eliminate duplicate rows from the query result in SQL is
cc. UNIQUE
#QN=50 Use of UNIQUE while defining an attribute of a table in SQL means that the attribute values are
cc. both (A) & (B)
#QN=29 If a transaction T has obtained an exclusive lock on item Q, then T can
cc. both read and write Q
#QN=80 For correct behaviour during recovery, undo and redo operation must be
cc. idempotent
#QN=48 The common column is eliminated in
cc. natural join
#QN=69 A list consists of last names, first names, addresses and pin codes. If all people in the list have the same last name and same pin code a useful key would be
cc. the compound key first name and last name
# Which one is not a step to design file organizations and indexes
choose security mechanisms
# Which statement is incorrect regards to the transaction
commited transaction cannot be aborted
# Which one is not a transformation rule for relation algebra operations to constrcut the query tree when doing query processing
commutavity of union and set difference
# indicator of high-quality data ensures that there are no missing values for given attribute in the system
completeness
#QN=11 According to the levels of abstraction, the schema at the intermediate level is called
conceptual schema
# 11. __ represents the level of detail in the factable
data granularity
# represents the level of detail in the factable
data granularity
# Which not building block
data schema
# __ focus is on how managers view the business
data warehouse
# __ may answer questions on overall process
data warehouse
# ___ reveals business trends
data warehouse
# Which of the following is main operation of the data mining
database segmentation
#QN=72 Which normal form is considered adequate for normal relational database design?
dd. 3NF
#QN=19 Block-interleaved distributed parity is RAID level
dd. 5
#QN=85 In tuple relational calculus P1 AND P2 is equivalent to
dd. ???P1OR ?P2?
#QN=40 R (A,B,C,D) is a relation. Which of the following does not have a lossless join dependency preserving BCNF decomposition
dd. A?BCD
#QN=108 Which of the following are integrity controls that a DBMS may support?
dd. All of the above
#QN=23 As per equivalence rules for query transformation, selection operation distributes over
dd. All of the above
#QN=71 The drawback of shadow paging technique are
dd. All of these
#QN=91 The data models defined by ANSI/SPARC architecture are
dd. Logical, physical and vieý
#QN=42 Maximum height of a B+ tree of order m with n key values is
dd. None of these
#QN=45 Which of the following concurrency control schemes is not based on the serializability property?
dd. None of these
#QN=93 A table can have only one
dd. Primary key
#QN=105 Which of the following is an advantage of partitioning?
dd. Security
#QN=28 The default level of consistency in SQL is
dd. Serializable
#QN=44 Which of the following statement on the view concept in SQL is invalid?
dd. The definition of a view should not have GROUP BY clause in it
#QN=33 If two relations R and S are joined, then the non matching tuples of both R and S are ignored in
dd. inner join
#QN=74 In a multi-user database, if two users wish to update the same record at the same time, they are prevented from doing so by
dd. record lock
# Which constraints used in specialization and generalization, choose two answers
disjoint+participation
# Which is not popular data warehouse architecture
distributed
# OLAP systems provide ____ and roll-up capabilities
drill-down
# accessible characteristic of strategic information means
easily accessible with intuitive access paths, and responsive for analysis
# Which of the following tolls is not one used to access data warehouse
extracting tool
# DOLAP allows download of "cube" structures to a desktop platform with the need for shared relational or cube server.
f
# Virtual cube is used to query two similar cubes by creating a third "virtual" cube by a join between two cubes
f
# All of the followings are most common mechanisms for conflict detection and resolution, excepts
hold for manual resolution
# Choose the correct statement
horizontal fragmentation defined using projection operation of relational algebra
# which statement is correct regards to the ordering of read/writes in the serializability of the transactions
if one transaction writes a data item and another reads or writes same data item, order of execution is important
# In table, there is only one___
index clustered
# 8. The presence of ____ diagram in the requirement....between operation and DW system
information package
# The presence of ____ diagram in the requirement....between operation and DW system
information package
# Which one is not property of the transaction
insolation
# An independent data mart
is filled with data from the operational environment, without a data warehouse
# The primary reason data marts are created is that
it is easier to develop several small data marts than to get everyone to agree on the organizational view of one large data warehouse.
# Which constraints do not exist in specialization and generalization, choose two answers?
joint+unparticipation
# which statement is correct regards to the two-phase locking (2PL)
leaving the release of all locks until end of transaction can prevent some problems
# The data warehouse is on information environment that:
makes the enterprise's current and historical information easily available for strategic decision making
# who needs strategic information in an enterprise
managers
# the definition and allocation of fragments carried out strategically to not achieve
maximum communication costs
# which one is not purpose of the normalization
minimal number of the relations access times
# All of the followings are query processing phases, excepts
normalization
# which one is not typical stage of the query decomposition phase when doing query processing
normalization analysis
# OLAP
online analytical processing
# Which statement(s) is (are) correct? 1) Metadata provides information on predefined queries 2) A metadata repository is like a general purpose directory tool
only statement 2
# Which one is not category of constraints of specialization and generalization
optional and joint
# which one is not category of constraints of specialization and generalization
optional and joint
# which one is basic client-server architecture of an object-oriented database system
page server
# which one is not a transition state of the transaction
partially arborted
# which constraints used in specialization and generalization, choose two answers
participation - disjoint
# (pivot for time o giua) Which operation is illustrated in the figure?
pivot
# Which one is not a phase of optimistic concurrency control techniques
prevetion
# 17. DW project life cycle
project plan, requirement definition ,.., ..,
# DW project life cycle
project plan, requirement definition ,.., ..,
# Multi-dimensional databases (MDDs) typically use ___________ formats to store pre-summarized cube structures
proprietary file
# The data warehouse is an informational environment that
provides an integrated and total view of the enterprise
# Which one is not typical stage of the query decomposition phase when doing query processing
query constructing
# Which one is not implementation issue of database replication
query execution
# which one is not implementation issue of databse replication
query execution
# which one is not transparency in a DDBMS
query processing transparency
# Which one is not a basic rules of locking
reads can conflict,...
# Which one is a DBMS transaction subsystem
recovery manager
# Which is NOT a key issue while planning for your data warehouse
requirement changes
# which statement is correct
secondary indexes can be created as many as necessary
# all of the following are main problems of data warehouse, excepts
short duration projects
# What is not advantage of the distributed DBMS
simplicity
# which one is disadvantages of ORDBMSs
simplicity of SQL
# All of the followings are type of attribute, excepts
single attribute
# (Slice for time o giua) Which operation is illustrated in the figure?
slice
# Which one is not a step in logical database design phase
split logical data models into global model
# In a traditional MIS system, there is an almost linear sequence of queries.
t
# in any analytical system, time is a critical dimension
t
# Bitmapped indexes are ideally suitable for ___ data
textual
# Which one should not use when choosing an index
that consist of long character strings
# Choose the incorrect statement about heterogeneous distributed DBMS
the intergration of the sites must be considered first
# Accurate requirements defination in a datawarehouse project is many times more important than in other types of projects
true
# Operational systems are the systems that are used to run the day-to-day core business of the company
true
# benefits from a data warehouse accrue only after the users put it to full use
true
# the detailed plan results in the defination of the transformation/conversion rules
true
# The followings are characteristics of the information extracting from database by using data mining tools, excepts
unxepected
# ________ means populating all the data warehouse table for the very first time
initial load
# _______ modeling technique is more appropriate for data warehouses.
physical
# Dimesional Modeling is suitable for ___
Data warehouse systems
# The STAR schema used for data design is a __________ consisting of fact and dimension tables.
Relational model
#QN=35 In 2NF
cc. No partial FDs exist
#QN=106 A correlated subquery is processed as a nested subquery.
Aa. Tru
#QN=125 The EXISTS keyword will be true if any row in the subquery meets the condition.
Aa. Tru
#QN=179 A distributed unit of work allows various statements within a unit of work to refer to multiple remote DBMS locations.
Aa. True
#QN=38 With failure transparency, all of the actions of a transaction are committed or none of them are committed
Aa. True
# Relational databases allow you to navigate the data in ____________ that is appropriate using the primary, foreign key structure within the data model
Any Direction
#QN=114 The primary goal of physical database design is data processing efficiency.
Bb. True
# many answer question on overall process
Business intelligence
#QN=74 Views constructed from SQL SELECT statements that conform to the SQL-92 standard may not contain:
Cc. ORDER BY
#QN=10 Which of the following are integrity controls that a DBMS may support?
Dd. All of the above
# 15. Source data in DW many come from
External data, production data, internal data, archived data
# The decision node of a decision tree tests how many attribute values _______.
Single
# Stored procedures have the advantage
That they can use iterative statements
# Which statement is correct regards to the deadlock?
Two-phase locking (2PL) eliminates the deadlock
# Which one is not an element of a database ER model
Verification
#QN=70 In b-tree the number of keys in each node is than the number of its children
aa. one less
#QN=77 Which of the following ensures the atomicity of the transaction?
aa. Transaction management component of DBMS
#QN=61 In E-R Diagram total participation is represented by
aa. double line
