Test your basic knowledge |

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. Explain why constraints are used when building tables.

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2. Which operator is most commonly used?
4
Details
Mathematical equations
UNION

3. Explain how Substitution Variables are used when writing scripts.
X
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.
A correct statement
DICTIONARY

4. Which format mask displays December 31st - 1999?
Data
When the table is small (unless your business rules require you too)
12:00:00 A.M
Month ddth - yyyy

5. What does SQL stand for?
DESC dict;
STORAGE
+
Structured Query Language

6. NUMBER functions can be...
Combine
Nested
X
Any

7. PAGESIZE
Columns
Default is 14; when you use the default - you repeat the heading every 14 rows.
Export Data
USER_ - ALL_ - DBA_ - and V$

8. You use the _________ keyword to add columns or constraints to a table.
UNION
ANY
ADD
RENAME just_two_more_weeks TO finally_i

9. The ____________ command makes changes permanent.
DD-MON-YY
UNION
MINUS
COMMIT

10. When using the following data: NUMBER(10 -4) - the # 4 is called the __________.
RENAME just_two_more_weeks TO finally_i
Scale
LENGTH
UTC

11. When is it not a good idea to use an index?
Parent table
Same
When the table is small (unless your business rules require you too)
VALUES clause of an INSERT statement

12. You can __________ DISTINCT and a GROUP BY clause in the same SELECT statement.
Combine
The way NULL values are treated
IN ANY ALL SOME
Asterisk

13. To join four tables - you must have at least _____ join conditions.
A correct statement
Nested
Three
CLOB

14. When using the following data: NUMBER(10 -4) - the lowest number you can possibly have is __________.
CLOB
Surrogate key
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
999999.9999

15. Users can only see changes made to a database once they have been...
Any
Committed
Any
Surrogate

16. The using clause of the ANSI join syntax always assumes an...
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
F12
Scalar
Equijoin and identical column names

17. When writing the syntax for finding information on three or more tables - the parenthesis around the ON clause is...
X
Optional
Static or dynamic
Three

18. _________ and __________ functions are opposites of each other and provide a value in a group of rows.
Both MIN and MAX
X
Null
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT

19. The ___________ operator tests whether a matching row cannot be found.
INNER JOIN
Default is 14; when you use the default - you repeat the heading every 14 rows.
X
ANY

20. Write an SQL statement for SQL *Plus in which you want any unique menu items to be displayed from the restaurant table
FALSE
SELECT DISTINCT menu FROM restaurant
All
The static data dictionary stores details about database objects - such as tables - indexes - and views. Whenever a new object is added or an object is changed - data about the object is recorded in the data dictionary.

21. It is considered good form to put all SQL commands in...
ANY
All caps
Month ddth - yyyy
Equijoin

22. The ROWID pseudocolumn is not an ________- but it acts like one.
Actual column
Implicit conversion
NATURAL JOIN
FALSE

23. SQL Developer's ____________________ option allows you to selectively export certain rows and columns.
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
CLOB
Export Data
SYSDATE

24. The purpose of the HAVING clause is to eliminate___________.
Rounded edges
UNION operator
Groups
Equijoin and identical column names

25. Write a statement for SQL*Plus that shows the dictionary.
The way NULL values are treated
DESC dict;
BETWEEN
FALSE

26. Joins involving multiple columns must always follow the ____________ relationship path.
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.
Primary key/foreign key
Mathematical equations

27. The COUNT function is useful for determining whether a table has...
Data
X
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.
Combine

28. What is the main difference between the NOT EXISTS and the NOT IN operators?
FALSE
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)
Details
The way NULL values are treated

29. What is the first column of a composite index called?
X
A correct statement
SYSDATE
Leading-edge

30. The time zone displacement value indicates the time difference from _______.
Parent table
UTC
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.

31. Write a solution that adds 20 minutes to a given date.
Optional
SELECT SYSDATE+1/96 - FROM dual
Null
When the table is small (unless your business rules require you too)

32. Oracle uses the outer join operator to indicate that nulls are shown for...
Non-matching rows
Equijoin and correlated subquery
Another null
Testing functions

33. The COUNT function uses the __________ wildcard.
Nested
All
Asterisk
NATURAL JOIN

34. ___________ subqueries allow you to reference columns from the outer query and execute the inner query repeatedly
Correlated
2000
Common column value
@ or START

35. In a view you can give a column a different name than it has in the...
Running a script file
DESC dict;
Parent table
B-Tree Index

36. The TIMESTAMP WITH LOCAL TIME ZONE data type allows...
ADD_MONTHS function
Fractional seconds
A correct statement
DROP INDEX need_to_pass_i

37. List the steps performed by a correlated subquery.
Hide data
STORAGE
MODIFY
**** 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

38. When you INSERT new information into a table - it is followed with a _______ keyword that contains the information that is going to be added to the table.
Static or dynamic
SELECT DISTINCT menu FROM restaurant
VALUES
Groups

39. What is the maximum value for a column defined as NUMBER(4 -2)?
99.99
MINUS
Implicit conversion
@ or START

40. When writing an ANSI outer join - the keywords _________ OUTER and _________ OUTER are added to the __________ keyword to indicate the rows from which table to use.
Correlated
Any
Asterisk
RIGHT LEFT JOIN

41. List the reasons that a subquery could not be unnested.
X
ADD_MONTHS function
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
Mathematical equations

42. Another name for a data dictionary view is __________________ or _________________.
Static or dynamic
A correct statement
Script
Scalar

43. The query retrieves more than 5 to 15 percent of the rows
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Equijoin and identical column names
Run scripts
ROLLBACK

44. Match each of the SQL commands on the left with a verb from the list.
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
UNION operator
Re-create
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.

45. What is Oracle's most popular index storage structure?
Equijoin
4000
X
B-Tree Index

46. Information that is returned after you run your statement are found in the __________ tab in SQL Developer.
Rounded edges
Results
Multiple rows
ADD

47. You can simplify the writing of SQL statements by writing SQL _________ that generate and execute other SQL statements.
Run scripts
DROP INDEX need_to_pass_i
IN ANY ALL SOME
Script

48. When returning multiple rows - a subquery must contain the _____ - _____ - _____ - or ______ operator - otherwise Oracle will return an error
Semicolon or forward slash
IN ANY ALL SOME
4000
Export Data

49. Explain how you can optimize your queries with subqueries and the main advantage of doing so.
Combine
Self-joins
99.99
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

50. Explain Flashback queries and how they are used. Give an example of a FLASHBACK_TRANSACTION query and explain what it does row by row.

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