Practice Q & a (Chapter 14 - 18)

Practice Q & A (Chapter 14 - 18) Chapter 14 1 . The USER_OBJECTS view shows information about synonyms, tables, views, and packages.

True False

2 . You can determine if a column has a default value by querying the data dictionary view USER_CONSTRAINTS.

True False

3 . Unique indexes created by the primary key constraint are not stored in the USER_INDEXES view. True False

4 . To find out how much space is allocated to a table or index, you can query the USER_SEGMENTS table. True False

5 . The following represents a multiline comment:

/* This is a comment that spawns several lines. */ True False

6 . The SET DEFINE OFF command turns the use of the substitution parameter, typically the ampersand (&) symbol, off.

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 1 of 10 Version Date: 5/4/2009 False

7 . The SPOOL command is a SQL*Plus command. True False

8 . The SET FEEDBACK 0 command shows the result of the SQL statement on the screen.

True False

9 . The v$ tables represent the static data dictionary. They can only be updated by Oracle.

True False

10. The following query specifies a data dictionary view. SELECT * FROM tabs

True False

Answers for "Chapter 14"

1. True The USER_OBJECTS view shows information about synonyms, tables, views, and packages.

2. False You can determine if a column has a default value by querying the data dictionary view USER_CONSTRAINTS. The view USER_TAB_COLUMNS shows this information.

3. False Unique indexes created by the primary key constraint are not stored in the USER_INDEXES view.

4. True To find out how much space is allocated to a table or index, you can query the USER_SEGMENTS table.

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 2 of 10 Version Date: 5/4/2009 5. True The following represents a multiline comment:

/* This is a comment that spawns several lines. */

6. True The SET DEFINE OFF command turns the use of the substitution parameter, typically the ampersand (&) symbol, off.

7. True The SPOOL command is a SQL*Plus command.

8. False The SET FEEDBACK 0 command shows the result of the SQL statement on the screen.

It shows the number of rows returned.

9. False The v$ tables represent the static data dictionary. They can only be updated by Oracle.

The v$ tables are referred to as the dynamic data dictionary views. They are only updated by Oracle.

10. True The following query specifies a data dictionary view.

SELECT * FROM tabs

Note: The TABS view is the synonym of the USER_TABLES view.

Chapter 15 1. Privileges, roles, and synonyms are all used to implement security in an Oracle database. False True 2. Any user can grant or revoke any type of system privilege to or from another user. True False 3. The data dictionary view USER_TAB_PRIVS_MADE lists details of table privilege grants performed by the current user. True False

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 3 of 10 Version Date: 5/4/2009 4. You cannot drop a user if objects exist in the user's schema. True False 5. Both object and system privileges can be granted through a single role to a user. True False

1. True Privileges, roles, and synonyms are all used to implement security in an Oracle database.

2. False Any user can grant or revoke any type of system privilege to or from another user.

3. True The data dictionary view USER_TAB_PRIVS_MADE lists details of table privilege grants performed by the current user.

4. False You cannot drop a user if objects exist in the user's schema.

Note: A user and its objects can be dropped simultaneously with the DROP USER CASCADE command.

5. True Both object and system privileges can be granted through a single role to a user

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 4 of 10 Version Date: 5/4/2009 Chapter 16 1. You identify the relationship between the parent and the child by placing the PRIOR operator before the parent column.

True False

2. To eliminate rows from the hierarchy tree, you use the WHERE clause.

True False

3. Choose the result that the following statement will return. SELECT REGEXP_SUBSTR('The plane leaves 02/05/04 at 04:23 pm.', '([0-1][0-9]|2[0-3]):[0-5][0-9]') FROM dual 02/05/04 4:23 pm 04:23 Invalid query

4. What is the result of this query? SELECT REGEXP_SUBSTR('This is a sentence.','.+[[:space:]]') FROM dual

This is a This is a sentence. This Invalid query

1. True You identify the relationship between the parent and the child by placing the PRIOR operator before the parent column.

2. True To eliminate rows from the hierarchy tree, you use the WHERE clause.

3. 04:23 Choose the result that the following statement will return. SELECT REGEXP_SUBSTR('The plane leaves 02/05/04 at 04:23 pm.',

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 5 of 10 Version Date: 5/4/2009 '([0-1][0-9]|2[0-3]):[0-5][0-9]') FROM dual

Note: The regular expression checks for the time, not the date. It requires that the string begins with a 0, 1 or 2. It validates that the hour is of a format between 00:00 and 23:59.

4. This is a What is the result of this query? SELECT REGEXP_SUBSTR('This is a sentence.','.+[[:space:]]') FROM dual

Note: Oracle's regular expression implementation is greedy and attempts to match as much as possible. The second answer choice is incorrect because the regular expression requires that the string end with a space at the end.

Chapter 17 1 . The OVER keyword as part of the analytical function syntax indicates that the function operates after the results of the FROM, WHERE, GROUP BY, and HAVING clauses have been formed. True False

2 . The ranking function DENSE_RANK assigns duplicate values a different rank.

True False

3 . The ORDER BY clause is required for all ranking functions.

True False

4 . Then WINDOWING clause allows you to compute cumulative, moving, and centered aggregates.

True False

5 . The RANGE keyword indicates a physical window.

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 6 of 10 Version Date: 5/4/2009 True False

6 . The GROUPING function helps determine if a row is a summary row or not. True False

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 7 of 10 Version Date: 5/4/2009 Answers for "Chapter 17"

1. True The OVER keyword as part of the analytical function syntax indicates that the function operates after the results of the FROM, WHERE, GROUP BY, and HAVING clauses have been formed.

2. False The ranking function DENSE_RANK assigns duplicate values a different rank.

The exception is COUNT(*), which does take NULL values into account.

3. True The ORDER BY clause is required for all ranking functions.

4. True Then WINDOWING clause allows you to compute cumulative, moving, and centered aggregates.

5. False The RANGE keyword indicates a physical window.

Note: The RANGE keyword indicates a logical window. A physical window is defined with the ROWS keyword.

6. True The GROUPING function helps determine if a row is a summary row or not.

Chapter 18 1 . One of the tasks performed when a SQL statement is parsed, is checking for valid syntax and user access rights.

True False

2 . A hint is enclosed by either a multiline comment with a plus sign (/*+ */) or prefixed by a single line comment with a plus (--+).

True False

3 . The ORDERED hint causes the tables to be joined in the order listed in the FROM clause of the query.

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 8 of 10 Version Date: 5/4/2009 True False

4 . The nested loop join is typically the fastest join type if you want to join the majority of data from two tables.

True False

5 . If your statements use bind variables, you can eliminate the parsing step.

True False

6 . If your data is uniformly distributed, histograms are useful to help determine the best execution plan.

True False

7 . When joining tables make sure to choose the table that returns the largest number of rows as the driving table. True False

1. True One of the tasks performed when a SQL statement is parsed, is checking for valid syntax and user access rights.

2. True A hint is enclosed by either a multiline comment with a plus sign (/*+ */) or prefixed by a single line comment with a plus (--+).

3. True The ORDERED hint causes the tables to be joined in the order listed in the FROM clause of the query.

4. False The nested loop join is typically the fastest join type if you want to join the majority of data from two tables.

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 9 of 10 Version Date: 5/4/2009 5. True If your statements use bind variables, you can eliminate the parsing step.

6. False If your data is uniformly distributed, histograms are useful to help determine the best execution plan. Histograms are useful if your data is skewed.

7. False When joining tables make sure to choose the table that returns the largest number of rows as the driving table.

Additional Q&A for Chapters 14-18; Oracle SQL by Example by Alice Rischert; Prentice Hall (2009) Page 10 of 10 Version Date: 5/4/2009