exam 4 questions
In which of the following situations would one have to use an outer join in order to obtain the desired results?
A report is desired that lists all customers and 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).
is used to generate appropriate SQL code on the fly as an application is processing.
Dynamic SQL
allows one to combine the INSERT and UPDATE operations.
MERGE command
A new set of analytical functions added in SQL:2008 is referred to as:
OLAP functions.
The ________ operator is used to combine the output from multiple queries into a single result table.
UNION
A join in which the joining condition is based on equality between values in the common columns is called a(n):
both equi-join and natural join.
A procedure is:
called, by name
There is a special operation in SQL to join a table to itself.
false
User-defined functions can improve system performance because they will be processed as sets rather than individually, thus reducing system overhead.
false
An interactive command that can be used to dynamically control a user session for appropriate integrity measures is:
set autocommit.
All of the following are guidelines for better query design EXCEPT:
use a lot of self-joins.
RANK and DENSE-RANK are examples of:
window functions.
________ use the result of the outer query to determine the processing of the inner query.
Correlated subqueries
causes two tables with a common domain to be combined into a single table or view.
join operation
Explicit commands to manage transactions are needed when:
multiple SQL commands must be run as part of a transaction.
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):
natural join
The most commonly used form of join operation is the:
natural join
While triggers run automatically, ________ do not and have to be called.
routines
SQL provides the ________ technique, which involves placing an inner query within the WHERE or HAVING clause of an outer query.
subquery
A type of query that is placed within a WHERE or HAVING clause of another query is called a:
subquery.
A named set of SQL statements that are considered when a data modification occurs are called:
triggers
A join in which the joining condition is based on equality between values in the common column is called an equi-join.
true
A procedure is run by calling it by its name.
true
Constraints are a special case of triggers.
true
Figuring out what attributes you want in your query before you write the query will help with query writing.
true
Joining tables or using a subquery may produce the same result.
true
RDBMSs store database definition information in system-created tables which can be considered a data dictionary.
true
SQL statements can be included in another language, such as C or Java.
true
The UNION clause is used to combine the output from multiple queries into a single result table.
true
User-defined data types:
can have defined functions and methods.
In order for two queries to be UNION-compatible, they must:
both output compatible data types for each column and return the same number of rows.
In SQL, a(n) ________ subquery is a type of subquery in which processing the inner query depends on data from the outer query.
correlated
A ________ is a temporary table used in the FROM clause of an SQL query.
derived table
________ takes a value of TRUE if a subquery returns an intermediate results table which contains one or more rows.
exists
A function has only input parameters but can return multiple values.
false
An equi-join is a join in which one of the duplicate columns is eliminated in the result table.
false
EXISTS takes a value of false if the subquery returns an intermediate result set.
false
It is better not to have a result set identified before writing GROUP BY and HAVING clauses for a query.
false
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):
outer join.
All of the following are advantages of SQL-invoked routines EXCEPT:
security
A type of join where a table is joined to itself is called a(n):
self-join
An operation to join a table to itself is called a(n):
self-join
All of the following are new data types added in SQL:2008 EXCEPT:
BIT.
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:
Persistent Stored Modules.
MULTISET is similar to the table datatype.
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.
false
Triggers can be used to ensure referential integrity, enforce business rules, create audit trails and replicate tables, but cannot call other triggers.
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.
false
Triggers have three parts: the event, the condition, and the action.
true
The outer join syntax does not apply easily to a join condition of more than ________ tables.
two
combine the output from multiple queries into a single result table.
union clause