Basic SQL Chapter 4

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What is the main reason for the commercial success of relational databases?

Relational database concept

ANSI SQL standard

SQL language (correct)

System R with Sequel

What is the year when E.Codd developed relational database concept?

1979

1974

1970 (correct)

1986

What is SQL used for?

Only for data definitions

For both data definitions and queries, and updates (correct)

Only for queries and updates

Only for security

What is the year when Oracle marketed the first relational DB with SQL?

1979 Signup and view all the answers

What is the acronym for Structured Query Language?

SQL Signup and view all the answers

What is the purpose of query optimization in query processing?

To select an efficient query evaluation plan Signup and view all the answers

What is the output of the parsing and translation step in query processing?

A parse tree Signup and view all the answers

What is the purpose of the evaluation step in query processing?

To execute the query and return the answers Signup and view all the answers

What is the function of the parser in query processing?

To verify the query is syntactically correct and construct a parse tree Signup and view all the answers

What is the purpose of relational algebra in query processing?

To represent the query in a formal language Signup and view all the answers

What is an advantage of using relational algebra in query processing?

It provides a formal language for representing queries Signup and view all the answers

What is the purpose of the CREATE DOMAIN construct in SQL?

To declare a customized data type Signup and view all the answers

Which of the following is a characteristic of the TIMESTAMP data type?

Includes the DATE and TIME fields, plus a minimum of six positions for decimal fractions of seconds Signup and view all the answers

What is the purpose of the INTERVAL data type?

To specify a relative value that can be used to increment or decrement an absolute value of a date, time, or timestamp Signup and view all the answers

What is the function of the LIKE comparison operator?

To perform string pattern matching Signup and view all the answers

What is the purpose of the EXCEPT operator in the given SQL query?

To retrieve data from two tables except for common rows Signup and view all the answers

What is the purpose of the UNION operator in the given SQL query?

To combine the results of two SELECT statements Signup and view all the answers

What is the purpose of the underscore (_) in pattern matching?

To replace a single character Signup and view all the answers

What is the function of the IS NULL operator?

To check if an attribute value is NULL Signup and view all the answers

What is the purpose of the BETWEEN operator?

To check if a value is within a range Signup and view all the answers

What is the purpose of the IN operator?

To check if a value is in a list of values Signup and view all the answers

What is the purpose of the ORDER BY clause?

To sort the rows in a particular order Signup and view all the answers

What is the purpose of the SELECT statement with the FROM and WHERE clauses?

To retrieve data from a table based on conditions Signup and view all the answers

What is the purpose of the INSERT command in SQL?

To add tuples to a relation Signup and view all the answers

What is the minimum number of clauses required in a SQL query?

Two Signup and view all the answers

What is the function of the FROM clause in a SQL query?

To specify the relation(s) to retrieve data from Signup and view all the answers

What is the purpose of the ORDER BY clause in a SQL query?

To sort data in a specific order Signup and view all the answers

What are the three commands used to modify a database?

INSERT, DELETE, UPDATE Signup and view all the answers

What is the purpose of the second form of the INSERT command?

To insert data into a relation with explicitly specified attribute names Signup and view all the answers