What is the disadvantage of cost based optimizers?

DBMS - DATA STORAGE AND QUERYING MCQ

• Which of the following is correct regarding Aggregate functions?
• Which of the following option is use to retrieval of data?
• Establishing limits on allowable property values, and specifying a set of acceptable, predefined options that can be assigned to a property are examples of:
• ______ is a special type of integrity constraint that relates two relations & maintains consistency across the relations
• Which of the following is a physical storage media ?
• Which of the following creates a virtual relation for storing the query ?
• Which of the following is the syntax for views where v is view name ?
• Here the tuples are selected from the view.Which one denotes the view ?
• Materialised views make sure that
• Updating the value of the view
• SQL view is said to be updatable (that is, inserts, updates or deletes can be applied on the view) if which of the following conditions are satisfied by the query defining the view?
• Which of the following is used at the end of the view to reject the tuples which do not satisfy the condition in where clause ?
• A relational database system needs to maintain data about the relations, such as the schema of the relations. This is called
• Relational schema and other metadata about relations are stored in a structure called the ____________
• ___________ is the collection of memory structures and Oracle background processes that operates against an Oracle database
• A ________ is a logical grouping of database objects, usually to facilitate security, performance, or the availability of database objects such as tables and indexes
• A tablespace is further broken down into ________
• __________ is a contiguous group of blocks allocated for use as part of a table, index, and so forth
• ________ is the smallest unit of allocation in an Oracle database
• DML is provided for
• The language used in application programs to request data from the DBMS is referred to as the
• The way a particular application views the data from the database that the application uses is a
• The DBMS language component which can be embedded in a program is
• A DBMS query language is designed to
• The full form of DDL is
• DDL Stands for ___________
• DML Stands for _____________
• Which of the following language is used to specify database Schema ?
• Set of definitions that are used to specify schema are expressed using __________
• Result of Compilation of DDL statement is stored in special file called as _________
• Data Dictionary is also called as _____________
• Data Dictionary contain one of the following entity inside it, Guess the answer
• Storage structure and Access methods used by database system are specified using ____________
• Data Manipulation Languages are used for
• There are _______ types of Data Manipulation Languages
• ________ it requires a user to specify what data are needed and how to get those data
• ________ it requires a user to specify what data are needed without specifying how to get those data
• The Statement that requests a retrieval of information from database is called as ________
• ________ is a portion of DML that involves information retrieval
• Which of the following is a database administrator's function?
• What is the language used by most of the DBMSs for helping their users to access data?
• Data item characteristics that are important in data management include
• Periodically adding, changing and deleting file records is called file
• The data dictionary tells the DBMS
• Sophisticated report generators can
• When you have finished entering information into a form
• If a calculation is embedded in a form
• A database management system might consist of application programs and a software package called
• In the DBM approach, application programs perform the
• When performing a look-up operation using a form
• A set of programs that handle a firm's data base responsibilities is called a
• The designer of a form includes
• A good query system
• The modify operation is likely to be done after
• One data dictionary software package is called
• One approach to standardizing storing of data
• Embedded pointer provide
• Data items grouped together for storage purposes are called a
• A list in alphabetical order
• Queries to a database
• The function which causes the retrieval of any kind of data from database is considered as
• The standardized types of database queries and methods of updating database are called
• The usage of operations with the help of arguments without considering the structure of operation implementation is classified as
• The specification given to database management system regarding the data whether it is string, integers or special characters is classified as
• The applications that are used for weather information or the collection of maps for geographical information is classified as
• One of the module in the database management system which is responsible for choosing efficient execution plan considering queries is considered as
• The procedure of storing the data on a medium of storage which is controlled by database management system is considered as
• The planning program which consolidates the functions of organizations such as sales, marketing, human resources and finance is classified as
• In external sorting, the number of runs that can be merged in every pass are called
• The files that can fit in available buffer space in phase of external sorting must be read into
• The concept which checks the syntax of query whether is written according to the rules of grammar is classified as
• The processor used to run the code of the queries of interpreted mode or compiled mode is classified as
• The procedure of sorting the algorithms for larger records that does not fit in the main memory and are stored on disk is classified as
• The files from which algorithms are selected for records are called
• The procedure of choosing a suitable query out of all the queries is classified as
• The representation of the query in the form of data structure is classified as
• The representation of the queries in the form of data structure graph is classified as
• In sort merge strategy, the small sub files sorted are called
• Which of the following are steps in query processing?
• A relational algebra operation annotated with instructions on how to evaluate it is called _______
• A sequence of primitive operations that can be used to evaluate a query are called as __________
• The lowest level operator to access data in query processing is _______
• Search algorithms that use an index are referred to as _________
• Sorting of relations that do not fit in memory is called as _______
• A selection of the form satisfying the intersection of all records satisfying individual simple conditions is
• A selection of the form satisfying the union of all records satisfying individual simple conditions is
• A selection of the form giving all the records not satisfying simple individual conditions is ______
• Which of the following can be implemented?
• If the results of one operation are passed on to the other, it is called as ________
• The result of each intermediate operation are created and then are used for valuation of the next level operations, this evaluation is called as ________
• If the system makes repeated requests for tuples from the operation at the top of the table, it is called as _________
• If the operations do not wait to produce tuples, then it is called as _________
• State true or false: Sorting is an inherently blocking operation
• State true or false: Join is an inherently blocking operation
• Which of the following techniques does not exist?
• State true or false: Hybrid hash join is partially pipelined on the probe relation
• The usage of two buffers, with one continuing execution of the algorithm while the other is written is called as __________
• Which of the following functions does an iterator not provide
• If on every legal database instant, the two expressions generate the same set of tuples, the expressions are called as
• State true or false: Selection operations are commutative
• Which of the following operations are associative
• Which of the following set operations is not commutative?
• State true or false: The projection operation does not distribute over the union operation
• If no rule can be derived from any combination of others then the set of rules is said to be ________
• Theta join operations are
• Which of the following operations is associative
• Which of the following set operations does the selection operation distribute over?
• State true or false: Multiple equivalence rules can be used one after the other on a query
• Which of the following information does the database system catalog store?
• Most databases store the distribution of values for each attribute as a __________
• What is the function of the equi-width histogram?
• What kind of a sample must be used for statistical analysis?
• The ________ SQL command generates statistics on a particular relation
• The union of all records satisfying the individual simple conditions Oi is called as ________
• The intersection of all records satisfying the individual simple conditions Oi is called as ________
• State true or false: Estimation of the size of the result of a join is not possible
• Size estimation can be done for which of the following processes?
• The size of a _____ is simply V(A,r) where r is the relation and A is a distinct value
• A ________ explores the space of all query evaluation plans that are equivalent to a given query
• What is the disadvantage of cost based optimizers?
• A particular sort order is said to be _________ sort order if it could be useful for a later operation
• The rule that allows transformation of a logical operation to a physical operation is called
• State true or false: Making multiple copies of the same sub-expressions must be avoided
• Optimizers use __________ to reduce the cost of optimization
• The join orders where the right operand of each join is in one of the initial relations are called as ________
• Caching and reuse of query plans is called as ________
• What technique is used for the evaluation of a query with a nested sub query?
• The process of replacing a nested query with a query with a join is known as _________
• A view whose contents are computed and stored is called as _______
• The task of keeping a view up to date with the underlying data is called as ________
• What is incremental materialized view maintenance?
• Which of the following is a type of materialized view management?
• What are differentials in view management?
• The sequence of queries that reflect the typical load on the system are known as ________
• The problem of an update affecting the execution of a query associated with the update is known as the _________
• Reducing the complexity of complex queries by similarly handling sub-queries is known as ______
• Which of the following is a multi-query optimization technique
• If a query is optimized without providing specific values for its parameters the technique is called __________
• A collection of data designed to be used by different people is called a/an
• Which of the following schemas does define a view or views of the database for particular users?
• Which of the following is an attribute that can uniquely identify a row in a table
• Which of the following terms does refer to the correctness and completeness of the data in a database
• The relationship between DEPARTMENT and EMPLOYEE is a
• A table can be logically connected to another table by defining a
• If the state of the database no longer reflects a real state of the world that the database is supposed to capture, then such a state is called
• Ensuring isolation property is the responsibility of the
• In query processing, the ___________ is the lowest-level operator to access data
• In a ____________ the system scans each file block and tests all records to see whether they satisfy the selection condition
• Index structures are referred to as __________ since they provide a path through which data can be located and accessed
• Search algorithms that use an index are referred to as
• Which algorithm uses equality comparison on a key attribute with a primary index to retrieve a single record that satisfies the corresponding equality condition
• The strategy can retrieve a single record if the equality condition is on a key;multiple records may be retrieved if the indexing field is not a key is
• The algorithm that uses a secondary ordered index to guide retrieval for comparison conditions involving <,≤,≥, or > is
• The ___ algorithm scans each index for pointers to tuples that satisfy an individual condition
• If access paths are available on all the conditions of a disjunctive selection, each index is scanned for pointers to tuples that satisfy the individual condition
• Conjunctive selection using one index
• A_____ is a query that retrieves rows from more than one table or view
• A condition is referred to as __________
• Which oracle is the join condition is specified using the WHERE clause
• Which are the join types in join condition
• Which product is returned in a join query have no join condition
• Which is a join condition contains an equality operator
• Which join refers to join records from the write table that have no matching key in the left table are include in the result set:
• Which operation are allowed in a join view
• Which view that contains more than one table in the top-level FROM clause of the SELECT statement
• Pictorial representation of an expression is called
• The results of each intermediate operation are created and then are used for evaluation of the next-level operations
• ______________ allows the algorithm to execute more quickly by performing CPU activity in parallel with I/O activity
• Pipelines can be executed in
• In a _________ the system makes repeated requests for tuples from the operation at the top of the pipeline
• In a _____________ operations do not wait for requests to produce tuples, but instead generate the tuples eagerly
• Each operation in a demand-driven pipeline can be implemented as an ____ that provides the following functions
• The iterator maintains the __________ of its execution in between calls, so that successive next() requests receive successive result tuples
• Tuples are generated ___________ in producer-driven pipelining, they are generated ________ on demand, in demand-driven pipelining
• When two inputs that we desire to pipeline into the join are not already sorted it is the _____________ technique
• Consider the following relational schemes for a library database:Assume {Author, Title} is the key for both schemes
• Let R(A,B,C,D,E,P,G) be a relational schema in which the following FDs are known to hold:
• Which of the following is/ are false for RAW mode of FOR XML
• ___________ refers to the ability of the system to recover committed transaction updates if either the system or the storage media fails
• Which utilities can we used to export data from sql server to a text file
• You have a column that will only contain values from 0 to 256. What is the most economical data type to use for the column
• Problems occurs if we don’t implement proper locking strategy
• Which of the following fixed database roles can add or remove user IDs
• By default sql server has ___________ isolation level
• Which feature converts row data to column for better analytical view?
• Which of the following statements is/are not true for SQL profiler
• Which global variables can be used to determine if a transaction is still open
• Which statement is used to define a cursor
• What is the default “SORT” order for a SQL
• Capabilities of RAISERROR
• How inserting data through stored procedure do reduces network traffic and increase database performance
• Stored procedures are safe from SQL injection attacks
• Which of the following connection type supports application role permissions and password encryption
• Cursor that reflects the changes made to the database table even after the result set is returned
• _______________ is a procedural extension of Oracle – SQL that offers language constructs similar to those in imperative programming languages
• ___________ combines the data manipulating power of SQL with the data processing power of Procedural languages
• _______________ has made PL/SQL code run faster without requiring any additional work on the part of the programmer
• A line of PL/SQL text contains groups of characters known as
• We use ______________ name PL/SQL program objects and units
• A ___________________ is an explicit numeric, character, string or Boolean value not represented by an identifier
• If no header is specified, the block is said to be an _______________ PL/SQL block
• _________________ is a sequence of zero or more characters enclosed by single quotes
• In _______________ the management of the password for the account can be handled outside of oracle such as operating system
• In ________________ of Oracle, the database administrator creates a user account in the database for each user who needs access

This question belongs to these collections

• DBMS - DATA STORAGE AND QUERYING MCQ

Similar questions