Query Processing and Optimization

_________ refers to the range of activities involved in extracting data from a database

• Query Optimization
• Query Processing
• Parsing
• Query Evaluation

The steps involved in processing __________

• Parsing and translation
• Optimization
• Evaluation
• All of Given

In query processing, system must first translate given query into which form?

• Internal form
• Physical form
• high level form
• New form

In generating the internal form of the query, the parser checks ___________

• Syntax of query
• Verifies relation name
• None of given
• Both of Given

Match the following: A) evaluation primitive B) query-execution plan c) query-execution engine 1) takes a query-evaluation plan, executes that plan, and returns the answers to the query 2) A relationalalgebra operation annotated with instructions on how to evaluate it 3)A sequence of primitive operations that can be used to evaluate a query

• A-2, B-3, C-1
• A-1, B-3, C-2
• A-3, B-1, C-2
• A-3, B-2, C-1

Which statement(S) is/are true? A) A query could be expressed in SQL several different ways. B) SQL query can be translated into a relationalalgebra expression in one of several ways. C) There are several ways to evaluate relational-algebra expressions D) We can execute each relational-algebra operation by one of several different algorithms.

• Only A,B
• Only A,C,D
• Only D
• All A,B,C,D

____________ is the process of selecting the most efficient query-evaluation plan from among the many strategies usually possible for processing a given query, especially if the query is complex.

• Query Processing
• Regulary Expression
• Query Optimization
• SQL

Query-evaluation plan that minimizes the cost of query evaluation is a duty of _____.

• Database System
• Database User
• Database Admin
• Programmer

___________ defines exactly what algorithm should be used for each operation, and how the execution of the operations should be coordinated

• Query Engine
• Evaluation plan
• Query Optimizer Engine
• Expression tree

Given a relational-algebra expression, it is the job of __________ to come up with _________ that computes the same result as the given expression, and is the least-costly way of generating the result

• query optimizer, expression tree
• query evaluation engine, expression tree
• query optimizer, query-evaluation plan
• query evaluation engine, query evaluation plan