Ch. 7 T/F
45) An equi-join is a join in which one of the duplicate columns is eliminated in the result table.
FALSE
49) The natural join is very rarely used.
FALSE
51) 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
52) One major disadvantage of the outer join is that information is easily lost.
FALSE
53) There is a special operation in SQL to join a table to itself.
FALSE
86) When a subquery is used in the FROM clause, it is called a denied table.
FALSE
46) A join in which the joining condition is based on equality between values in the common column is called a(n) equi-join.
TRUE
47) The joining condition of an equi-join is based upon an equality.
TRUE
50) An SQL query that implements an outer join will return rows that do not have matching values in common columns.
TRUE
64) The UNION clause is used to combine the output from multiple queries into a single result table.
TRUE
66) Figuring out what attributes you want in your query before you write the query will help with query writing.
TRUE
77) Persistent Stored Modules are extensions defined in SQL:1999 that include the capability to add and drop modules of code.
TRUE
79) Constraints are a special case of triggers.
TRUE
81) Triggers have three parts: the event, the condition, and the action.
TRUE
84) A procedure is run by calling it by its name.
TRUE
85) SQL statements can be included in another language, such as C or Java.
TRUE
60) A subquery in which processing the inner query depends on data from the outer query is called a codependent query.
FALSE
54) Joining tables or using a subquery may produce the same result.
TRUE
62) A correlated subquery is executed once for each iteration through the outer loop.
TRUE
69) Correlated subqueries are less efficient than queries that do not use nesting.
TRUE
71) 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.
TRUE
73) RDBMSs store database definition information in system-created tables which can be considered a data dictionary.
TRUE
63) Subqueries can only be used in the WHERE clause.
FALSE
65) IF-THEN-ELSE logical processing cannot be accomplished within an SQL statement.
FALSE
The following query will execute without errors. select customer.customer_name, salesman.sales_quota from customer where customer.salesman_id = (select salesman_id where lname = 'SMITH');
FALSE
58) EXISTS takes a value of false if the subquery returns an intermediate result set.
FALSE
67) It is better not to have a result set identified before writing GROUP BY and HAVING clauses for a query.
FALSE
68) 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
70) Combining a table with itself results in a faster query.
FALSE
72) 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.
FALSE
74) DBA_USERS contains comments on all tables in an Oracle database.
FALSE
76) MULTISET is similar to the table datatype.
FALSE
78) A routine is a named set of SQL statements that are considered when a data modification occurs.
FALSE
80) Triggers can be used to ensure referential integrity, enforce business rules, create audit trails and replicate tables, but cannot call other triggers.
FALSE
82) A function has only input parameters but can return multiple values.
FALSE
88) User-defined functions can improve system performance because they will be processed as sets rather than individually, thus reducing system overhead.
FALSE
89) 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.
FALSE
48) 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.
TRUE
55) The following queries produce the same results. select customer_name, customer_city from customer, salesman where customer.salesman_id = salesman.salesman_id and salesman.lname = 'SMITH'; select customer_name, customer_city from customer where customer.salesman_id = (select salesman_id from salesman where lname = 'SMITH')
TRUE
57) 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.
TRUE
59) 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.
TRUE
61) The following SQL statement is an example of a correlated subquery. select first_name, last_name, total_sales from salesman s1 where total_sales > all (select total_sales from salesman s2 where s1.salesman_id != s2.salesman_id);
TRUE
75) SQL:2008 allows one to calculate linear regressions, moving averages and correlations without moving the data outside of the database.
TRUE
83) The advantages of SQL-invoked routines are flexibility, efficiency, shareability and applicability.
TRUE
87) Establishing IF-THEN-ELSE logical processing within an SQL statement can now be accomplished by using the CASE keyword in a statement.
TRUE
90) A trigger is a named set of SQL statements that are considered when a data modification occurs.
TRUE
