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Oracle SQL

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Write a statement for SQL*Plus that shows the dictionary.
Script
DESC dict;
Multiple rows
Subqueries allow you to nest multiple queries into each other. This gives you the ability to use one statement to break down a problem into individual components. Without nesting queries - you would be required to have multiple queries which could be

2. Explain in detail the impact of INDEXES and how they are used by Oracle.
Null
UNION
To achieve good performance for data retrieval and data manipulation statements Oracle uses indexes. In the same way you would use an index in the back of a book to quickly find information - Oracle uses indexes to speed up data retrieval. If the app
Fractional seconds

3. When using the data NUMBER(10 -4) there will be _______ digits following the decimal point.
**** Select a row from the outer query - Determine the value of the correlated column - Execute the inner query for each record of the outer query. - Feed the results of the inner query to the outer query and evaluate it. It if satisfies the criteria
Equijoin and identical column names
99.99
4

4. LINESIZE
Nested
Running a script file
BETWEEN
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.

5. Self-joins are useful for performing comparisons and checking for ___________ in data.
Run scripts
Inconsistencies
FALSE
Scalar

6. Checks whether any value in the list makes the condition true.
The SPOOL command - together with a file name - spools any subsequently issued SQL Plus or SQL command to a file. Just as with other file names - you can add a path to store the file in a directory other than your SQL Plus default directory. SQL Deve
4
Any
Surrogate key

7. The TRUNC function on a date without a format model truncates the timestamp to...
Correlated
12:00:00 A.M
Recursive
Self-joins

8. What is the Oracle data dictionary called that contains a set of tables and views containing the data about the database?
Retrieve
ALL_OBJECTS
Same
Asterisk

9. The purpose of the HAVING clause is to eliminate___________.
DICTIONARY
Columns
Groups
The way NULL values are treated

10. ____________ are useful for analyzing and exploring the relationships within your data
To achieve good performance for data retrieval and data manipulation statements Oracle uses indexes. In the same way you would use an index in the back of a book to quickly find information - Oracle uses indexes to speed up data retrieval. If the app
Business problems
Self-joins
When you want to run the same script repeatedly - but want to be able to change a variable you would use a substitution variable. During the execution of the script the user will be prompted to input the variable to use.

11. The key that most database designers prefer and is chosen by the system is the _____________ key.
999999.9999
X
Surrogate
Same

12. What does the following function return? SELECT LENGTH(NULL) - FROM dual
SYSDATE
Nested
Null
FALSE

13. To join four tables - you must have at least _____ join conditions.
When you issue a INSERT - UPDATE - DELETE - or MERGE statement - Oracle automatically locks the modified rows. The lock prevents other sessions from making changes to these rows. The lock is released when the session initiating change commits or roll
Three
All
Another null

14. The _______ function lets you perform if-then-else functionality with the SQL language.
Both MIN and MAX
DECODE
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Has not changed the name

15. The NEXTVAL and CURRVAL pseudocolumns can be used in which of the following SQL constructs? Select all that apply.
Month ddth - yyyy
SELECT SYSDATE+1/96 - FROM dual
ADD_MONTHS function
VALUES clause of an INSERT statement

16. The __________ operator is inclusive of the two values specified.
Combine
Semicolon or forward slash
Month ddth - yyyy
BETWEEN

17. List the reasons that a subquery could not be unnested.
DICT_COLUMNS
Data
Any
X

18. What is the name of the view where you can find the collection of static and data dictionary tables and views - along with their descriptions?
DICTIONARY
Black
MODIFY
RENAME just_two_more_weeks TO finally_i

19. The TIMESTAMP WITH LOCAL TIME ZONE data type allows...
Fractional seconds
INTERSECT
RUN SCRIPT
Crow's foot

20. How many characters can you have using the VARCHAR data type?
2000
Re-create
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.
4000

21. SELECT * FROM instructor ORDER BY phone
A correct statement
Combine
Equijoin and correlated subquery
SUM

22. What do views do that makes them so useful for security?
ON
Hide data
RIGHT LEFT JOIN
Surrogate

23. When you create a report in SQL Developer all the column names must match identically the names of the columns found in the tables you are referencing.
FALSE
The way NULL values are treated
BETWEEN
Non-matching rows

24. The _______ operator determines common rows.
Surrogate
DICTIONARY
MODIFY
INTERSECT

25. The ROWID pseudocolumn is not an ________- but it acts like one.
Precision
Actual column
Committed
Null

26. The same function can be used ______ in a SELECT statement.
BETWEEN
Logical unit of work
Twice
Correlated

27. Match each of the SQL commands on the left with a verb from the list.
Static or dynamic
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
Run scripts
UNION operator

28. What is the name of the key automatically generated from a sequence?
+
UNION operator
Script
Surrogate key

29. When returning multiple rows - a subquery must contain the _____ - _____ - _____ - or ______ operator - otherwise Oracle will return an error
BETWEEN
Equijoin
FALSE
IN ANY ALL SOME

30. ___________ subqueries allow you to reference columns from the outer query and execute the inner query repeatedly
The main components of a ROWID are the data object number - the number of the data block - the numbers of rows within the data block - and the data file number.
Inconsistencies
V$
Correlated

31. The COUNT function is useful for determining whether a table has...
Extra spaces
Data
RUN SCRIPT
Constraints are used to enforce the business rules of a system. For instance - 'The salary of an employee may not be a negative number' may be enforced with a check constraint on the salary column. Constraints also ensure integrity and data consisten

32. When you run a script in SQL*Plus you must give the...
ALL_OBJECTS
FALSE
Common column value
Location of the file

33. The DUAL table can be used for...
Combine
Both MIN and MAX
Testing functions
STORAGE

34. Which one of the following string functions tells you how many characters are in a string?
Hide data
DICT_COLUMNS
V$
LENGTH

35. Users can only see changes made to a database once they have been...
CLOB
Committed
Testing functions
Details

36. Queries that are found in parentheses are done first - just as in the order of operations when doing...
DICTIONARY
4
Mathematical equations
STORAGE

37. To restart a sequence at a lower number - you can drop and ________ the sequence.
Re-create
Black
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Logical unit of work

38. You use the _________ keyword to add columns or constraints to a table.
12:00:00 A.M
ADD
Both MIN and MAX
Extra spaces

39. What is Oracle's most popular index storage structure?
Re-create
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
B-Tree Index
VALUES

40. Explain how the SPOOL command is used and what program it can be used in.
Scale
The SPOOL command - together with a file name - spools any subsequently issued SQL Plus or SQL command to a file. Just as with other file names - you can add a path to store the file in a directory other than your SQL Plus default directory. SQL Deve
Default is 14; when you use the default - you repeat the heading every 14 rows.
MODIFY

41. The _______ function adds values together for a group of rows.
SUM
ADD_MONTHS function
MODIFY
All caps

42. The Nonequijoin can use the ________________ operator to construct joins that are not based on equality of values.
Any
BETWEEN
Same
ALL_OBJECTS

43. What is the main difference between the NOT EXISTS and the NOT IN operators?
The way NULL values are treated
Has not changed the name
Constraints are used to enforce the business rules of a system. For instance - 'The salary of an employee may not be a negative number' may be enforced with a check constraint on the salary column. Constraints also ensure integrity and data consisten
Inconsistencies

44. Explicit data type conversion is preferable to Oracle's...
KEEP INDEX
Implicit conversion
Columns
Business problems

45. What is the first column of a composite index called?
Both MIN and MAX
Leading-edge
ALL_OBJECTS
SET clause of an UPDATE statement

46. FEEDBACK
All
Both MIN and MAX
Command returns the number of records returned by a query.
Location of the file

47. You use the __________ keyword to change characteristics of a column.
Orphan
GROUP BY
Equijoin and correlated subquery
MODIFY

48. To place a line comment in your SQL statements - you first place a // at the beginning of the line.
Script
Orable's flashback query feature allows you to look at values of a query at a specific time in the past - such as before specfic DML statements occured. This can be usefull in case a suer accidentally performs an unintended but committed DML change.
FALSE
Both MIN and MAX

49. A _____ is a query definition stored in the database that looks just like a table - but does not have any physical rows
ADD_MONTHS function
Extra spaces
Run scripts
X

50. The ______ depicts the M of a 1:M relationship.

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