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. Which operator is most commonly used?
RIGHT LEFT JOIN
Export Data
Time zone
UNION

2. 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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3. What is the syntax used to indicate that you are using the Oracle Outer Join operator?
Rounded edges
Business problems
+
Leading-edge

4. Explain what is found in the All Objects report folder in SQL Developer
Retrieve
The indexed column is part of an expression. In this case - consider creating a function-based index instead
ADD
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.

5. To join four tables - you must have at least _____ join conditions.
Details
Three
**** 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
All caps

6. A join across three tables can be expressed with the ________ join syntax.
ANSI
BETWEEN
Parent table
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.

7. The DUAL table can be used for...
COMMIT
Testing functions
Equijoin
Has not changed the name

8. What is the main difference between the NOT EXISTS and the NOT IN operators?
Details
The way NULL values are treated
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
Semicolon or forward slash

9. You can simplify the writing of SQL statements by writing SQL _________ that generate and execute other SQL statements.
VALUES clause of an INSERT statement
VALUES
FALSE
Script

10. Explain how Substitution Variables are used when writing scripts.
Groups
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.
ROLLBACK
The way NULL values are treated

11. Explain how you can optimize your queries with subqueries and the main advantage of doing so.
STORAGE
@ or START
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
Orphan

12. The purpose of the HAVING clause is to eliminate___________.
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
DECODE
RIGHT LEFT JOIN
Groups

13. List the different types of data dictionary views.
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
RENAME just_two_more_weeks TO finally_i
MINUS
USER_ - ALL_ - DBA_ - and V$

14. What do views do that makes them so useful for security?
B-Tree Index
Data
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Hide data

15. In a view you can give a column a different name than it has in the...
Another null
Parent table
VALUES
User-defined reports

16. What is the first column of a composite index called?
Orphan
Leading-edge
Three
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.

17. The term ____________ ___________ is used to express a join that satisfies the join condition.
IN ANY ALL SOME
INNER JOIN
Hide data
LIKE

18. When you want to run a script in either SQL*Plus or SQL Developer - you can use a ______ or the _________ command.
@ or START
Hide data
Common column value
All

19. The key that most database designers prefer and is chosen by the system is the _____________ key.
Committed
Location of the file
Surrogate
Black

20. When column names on the tables are different - you use the ______ condition.
Testing functions
ON
RUN SCRIPT
@ or START

21. _________ and __________ functions are opposites of each other and provide a value in a group of rows.
Both MIN and MAX
Parent table
The way NULL values are treated
NATURAL JOIN

22. 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.
COMMIT
RIGHT LEFT JOIN
X
Scale

23. Returns rows if the condition is true for all the values in the list
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
STORAGE
All
Business problems

24. You use the _________ keyword to add columns or constraints to a table.
ADD
The way NULL values are treated
Nested
Static or dynamic

25. A transaction is a...
Logical unit of work
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
Precision
SELECT SYSDATE+1/96 - FROM dual

26. Match each of the SQL commands on the left with a verb from the list.
All caps
Retrieve
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
999999.9999

27. You can __________ DISTINCT and a GROUP BY clause in the same SELECT statement.
Combine
ADD
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
Another null

28. The Nonequijoin can use the ________________ operator to construct joins that are not based on equality of values.
RENAME just_two_more_weeks TO finally_i
X
BETWEEN
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)

29. When returning multiple rows - a subquery must contain the _____ - _____ - _____ - or ______ operator - otherwise Oracle will return an error
IN ANY ALL SOME
Inconsistencies
Export Data
Multiple rows

30. The time zone displacement value indicates the time difference from _______.
Combine
UTC
BETWEEN
+

31. The ____________ icon allows you to execute multiple statements and emulates SQL *Plus as much as possible.
SELECT SYSDATE+1/96 - FROM dual
SELECT DISTINCT menu FROM restaurant
Hide data
RUN SCRIPT

32. The ________ operator cannot compare against a list of values.
LIKE
Load the file into the SQL Statement Box - by opening the location the file is stored and inserting it into the statement Box. Next you can press the F5 key.
MODIFY
Location of the file

33. What is the tab in SQL Developer where data dictionary view information can be found?
MODIFY
Details
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
IN ANY ALL SOME

34. The COUNT function uses the __________ wildcard.
Asterisk
Black
Crow's foot
Same

35. Checks whether any value in the list makes the condition true.
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.
Static or dynamic
Business problems
Any

36. Self-joins are useful for performing comparisons and checking for ___________ in data.
RENAME just_two_more_weeks TO finally_i
Any
Inconsistencies
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.

37. When you run a script in SQL*Plus you must give the...
99.99
Location of the file
Command returns the number of records returned by a query.
12:00:00 A.M

38. Explain the differences in how an ANSI Full Outer Join and a Full Outer Join using the UNION Operator work
Actual column
X
Any
Fractional seconds

39. Checks whether any value in the list makes the condition true.
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.
All
When the table is small (unless your business rules require you too)
Any

40. Explain in detail the impact of INDEXES and how they are used by Oracle.
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
Equijoin and correlated subquery
Structured Query Language
Recursive

41. ____________ are useful for analyzing and exploring the relationships within your data
SUM
Re-create
TO_CHAR function
Self-joins

42. ___________ subqueries allow you to reference columns from the outer query and execute the inner query repeatedly
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.
Correlated
ADD_MONTHS function
Nested

43. What does the following function return? SELECT LENGTH(NULL) - FROM dual
Black
Null
DESC dict;
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.

44. The NEXTVAL and CURRVAL pseudocolumns can be used in which of the following SQL constructs? Select all that apply.
VALUES clause of an INSERT statement
Implicit conversion
Correlated
Surrogate

45. Converting a text literal to DATE format requires the use of the...
Running a script file
Business problems
TO_CHAR function
Precision

46. Explain how Oracle treats locks when a database is being updated and needs to be viewed by other users.
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
TO_CHAR function
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Details

47. Write a statement that drops the index need_to_pass_i
DROP INDEX need_to_pass_i
LIKE
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.
DD-MON-YY

48. The TRUNC function on a date without a format model truncates the timestamp to...
A correct statement
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.
12:00:00 A.M
Implicit conversion

49. Write a statement for SQL*Plus that shows the dictionary.
Twice
4000
Same
DESC dict;

50. The ROWID pseudocolumn is not an ________- but it acts like one.
Black
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
Actual column
Running a script file