Modern Database Management - Chapter 7

equi-join, natural join

A join in which the joining condition is based on equality between values in the common columns is called a(n):

all of the above.

A procedure is:

Answer: FALSE

A routine is a named set of SQL statements that are considered when a data modification occurs.

self-join.

An operation to join a table to itself is called a:

Answer: TRUE

Constraints are a special case of triggers.

Answer: TRUE

Figuring out what attributes you want in your query before you write the query will help with query writing.

Answer: FALSE

IF-THEN-ELSE logical processing cannot be accomplished within an SQL statement.

dba_tables

If the DBA wishes to describe all tables in the database, which data dictionary view should be accessed in Oracle?

correlated

In SQL, a(n) ________ subquery is a type of subquery in which processing the inner query depends on data from the outer query.

both output compatible data types for each column and return the same number of rows.

In order for two queries to be UNION-compatible, they must:

Answer: TRUE

Persistent Stored Modules are extensions defined in SQL:1999 that include the capability to add and drop modules of code.

all of the above.

SQL-invoked routines can be:

Answer: TRUE

SQL:2008 allows one to calculate linear regressions, moving averages and correlations without moving the data outside of the database.

Answer: FALSE

Specifying the attribute names in the SELECT statement will make it easier to find errors in queries and also correct for problems that may occur in the base system.

Answer: FALSE

User-defined functions can improve system performance because they will be processed as sets rather than individually, thus reducing system overhead.

Answer: TRUE

When EXISTS or NOT EXISTS is used in a subquery, the select list of the subquery will usually just select all columns as a placeholder because it doesn't matter which columns are returned.

natural join.

A join that is based upon equality between values in two common columns with the same name and where one duplicate column has been removed is called a(n):

triggers.

A named set of SQL statements that are considered when a data modification occurs are called:

self-join.

A type of join where a table is joined to itself is called a(n):

selection.

All of the following are part of the coding structure for triggers EXCEPT:

Answer: TRUE

An SQL query that implements an outer join will return rows that do not have matching values in common columns.

Answer: FALSE

Combining a table with itself results in a faster query.

Answer: FALSE

DBA_USERS contains comments on all tables in an Oracle database.

is used to generate appropriate SQL code on the fly as an application is processing.

Dynamic SQL:

hard-coded SQL statements included in a program written in another language.

Embedded SQL consists of:

using the CASE keyword in a statement.

Establishing IF-THEN-ELSE logical processing within an SQL statement can be accomplished by:

EXEC SQL

In order to embed SQL inside of another language, the ________ statement must be placed before the SQL in the host language.

Answer: TRUE

In order to find out what customers have not placed an order for a particular item, one might use the NOT qualifier along with the IN qualifier.

information is not lost.

One major advantage of the outer join is that:

Answer: FALSE

One major disadvantage of the outer join is that information is easily lost.

Answer: FALSE

Persistent Sorted Modules are extensions defined in SQL-99 that include the capability to create and drop modules of code stored in the database schema across user sessions.

Answer: FALSE

There is a special operation in SQL to join a table to itself.

Answer: FALSE

Triggers can be used to ensure referential integrity, enforce business rules, create audit trails, replicate tables, but cannot call other triggers.

transactions are processed as sets, reducing system overhead.

User-defined transactions can improve system performance because:

derived table

A ________ is a temporary table used in the FROM clause of an SQL query.

Answer: TRUE

A natural join is the same as an equi-join, except that it is performed over matching columns that have been defined with the same name, and one of the duplicate columns is eliminated.

OLAP functions.

A new set of analytical functions added in SQL:2008 is referred to as:

Answer: TRUE

A procedure is run by calling it by its name.

Answer: FALSE

A subquery in which processing the inner query depends on data from the outer query is called a codependent query.

Answer: FALSE

Subqueries can only be used in the WHERE clause.

combine the output from multiple queries into a single result table.

The UNION clause is used to:

natural join.

The most commonly used form of join operation is the:

Correlated subqueries

________ use the result of the outer query to determine the processing of the inner query.

Answer: TRUE

A transaction is the complete set of closely related update commands that must all be done, or none of them done, for the database to remain valid.

Answer: TRUE

A trigger is a named set of SQL statements that are considered when a data modification occurs.

Answer: TRUE

Correlated subqueries are less efficient than queries that do not use nesting.

Answer: TRUE

Joining tables or using a subquery may produce the same result.

security.

All of the following are advantages of SQL-invoked routines EXCEPT:

use a lot of self-joins.

All of the following are guidelines for better query design EXCEPT:

Answer: TRUE

RDBMSs store database definition information in system-created tables which can be considered a data dictionary.

subquery

SQL provides the ________ technique, which involves placing an inner query within the WHERE or HAVING clause of an outer query.

can have all of the above.

User-defined data types:

Answer: FALSE

Using an outer join produces this information: rows that do not have matching values in common columns are not included in the result table.

Answer: FALSE

When a subquery is used in the FROM clause, it is called a denied table.

routines

While triggers run automatically, ________ do not and have to be called.

Answer: TRUE

A join in which the joining condition is based on equality between values in the common column is called a(n) equi-join.

causes two tables with a common domain to be combined into a single table or view.

A join operation:

Answer: TRUE

A correlated subquery is executed once for each iteration through the outer loop.

Answer: FALSE

A function has only input parameters but can return multiple values.

outer join.

A join in which rows that do not have matching values in common columns are still included in the result table is called a(n):

subquery.

A type of query that is placed within a WHERE or HAVING clause of another query is called a:

BIT.

All of the following are new data types added in SQL:200n EXCEPT:

Answer: FALSE

An equi-join is a join in which one of the duplicate columns is eliminated in the result table.

set autocommit.

An interactive command that can be used to dynamically control a user session for appropriate integrity measures is:

Answer: FALSE

EXISTS takes a value of false if the subquery returns an intermediate result set.

TRUE

EXISTS will take a value of ________ if the subquery returns an intermediate results table which contains one or more rows.

Answer: TRUE

Establishing IF-THEN-ELSE logical processing within an SQL statement can now be accomplished by using the CASE keyword in a statement.

multiple SQL commands must be run as part of a transaction.

Explicit commands to manage transactions are needed when:

Persistent Stored Modules.

Extensions defined in SQL-99 that include the capability to create and drop modules of code stored in the database schema across user sessions are called:

A report is desired that lists all customers, the total of their orders during the most recent month, and includes customers who did not place an order during the month (their total will be zero).

In which of the following situations would one have to use an outer join in order to obtain the desired results?

Answer: FALSE

It is better not to have a result set identified before writing GROUP BY and HAVING clauses for a query.

Answer: FALSE

MULTISET is similar to the table datatype.

window functions.

RANK and DENSE-RANK are examples of:

Answer: TRUE

SQL statements can be included in another language, such as C or Java.

allows one to combine the INSERT and UPDATE operations.

The MERGE command:

Answer: TRUE

The UNION clause is used to combine the output from multiple queries into a single result table.

DBA_USERS

The ________ DBA view shows information about all users of the database in Oracle.

UNION

The ________ clause is used to combine the output from multiple queries into a single result table.

Answer: TRUE

The advantages of SQL-invoked routines are flexibility, efficiency, shareability and applicability.

Answer: TRUE

The joining condition of an equi-join is based upon an equality.

Answer: FALSE

The natural join is very rarely used.

two

The outer join syntax does not apply easily to a join condition of more than ________ tables.

Answer: FALSE

Transaction integrity commands are not used to identify whole units of database changes that must be completed in full for the database to retain integrity.

Answer: TRUE

Triggers have three parts: the event, the condition, and the action.

MULTISET

________ differs from array because it can contain duplicates.

Exists

________ takes a value of true if a subquery returns an intermediate results table which contains one or more rows.