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. What does the following function return? SELECT LENGTH(NULL) - FROM dual
Export Data
@ or START
Null
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.

2. The same function can be used ______ in a SELECT statement.
@ or START
Black
Twice
DESC dict;

3. The ____________ keywords and the USING clause of the ANSI join syntax are mutually exclusive.
All
Three
CLOB
NATURAL JOIN

4. When writing the syntax for finding information on three or more tables - the parenthesis around the ON clause is...
Implicit conversion
Optional
GROUP BY
99.99

5. To equijoin a table with another table involves matching the...
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
Common column value
SELECT SYSDATE+1/96 - FROM dual
RIGHT LEFT JOIN

6. A transaction is a...
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.
Logical unit of work
Parent table
F12

7. List 4 aggregate functions
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)
Extra spaces
Equijoin and correlated subquery
USER_ - ALL_ - DBA_ - and V$

8. Write a statement for SQL*Plus that shows the dictionary.
Three
X
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.
DESC dict;

9. Explain how you can optimize your queries with subqueries and the main advantage of doing so.
Any
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
Static or dynamic
Asterisk

10. What is the most common DATE format found in SQL?
Primary key/foreign key
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.
Asterisk
DD-MON-YY

11. What is the maximum value for a column defined as NUMBER(4 -2)?
99.99
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
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.
MODIFY

12. The focus of the logical data model is _____________
ADD_MONTHS function
ON
Business problems
Structured Query Language

13. Dynamic views begin with a ___________.
999999.9999
V$
Export Data
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)

14. What is the main difference between the NOT EXISTS and the NOT IN operators?
Crow's foot
DESC dict;
The way NULL values are treated
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.

15. Explain what a static data dictionary view is and how it is used
All
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
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.
SUM

16. SELECT LIST of a subquery in an INSERT statement
ADD
INTERSECT
Nested
SET clause of an UPDATE statement

17. Converting a text literal to DATE format requires the use of the...
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.
Semicolon or forward slash
TO_CHAR function
UNION

18. What is the name of the key automatically generated from a sequence?
Any
Command returns the number of records returned by a query.
Scale
Surrogate key

19. ___________ subqueries allow you to reference columns from the outer query and execute the inner query repeatedly
X
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.
Correlated
Parent table

20. The time zone displacement value indicates the time difference from _______.
ANSI
UTC
Export Data
Structured Query Language

21. What is the command you would type into SQL*Plus if you needed to know the definition for each column of a table?
DICTIONARY
Results
ALL_OBJECTS
DICT_COLUMNS

22. What is the keyboard shortcut for the ROLLBACK command?
F12
A correct statement
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
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

23. To revert back to a state that happened before you ran your change statement - you issue a ____________ command.
Committed
ROLLBACK
Mathematical equations
Nested

24. Comparison operators can compare multiple _________________.
Both MIN and MAX
All
Columns
RENAME just_two_more_weeks TO finally_i

25. 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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26. The ________ operator cannot compare against a list of values.
B-Tree Index
X
DESC dict;
LIKE

27. SQL Developer provides an extensive list of useful reports and offers the capability to create your own...
Combine
Null
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.
User-defined reports

28. What is the first column of a composite index called?
Any
TO_CHAR function
FALSE
Leading-edge

29. The COUNT function is useful for determining whether a table has...
999999.9999
Data
Equijoin
Rounded edges

30. What is the Oracle data dictionary called that contains a set of tables and views containing the data about the database?
SUM
Scalar
DECODE
ALL_OBJECTS

31. Write a statement that drops the index need_to_pass_i
DROP INDEX need_to_pass_i
Export Data
Both MIN and MAX
STORAGE

32. The _______ function lets you perform if-then-else functionality with the SQL language.
DECODE
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.
BETWEEN
Actual column

33. Another name for a data dictionary view is __________________ or _________________.
RUN SCRIPT
The way NULL values are treated
Static or dynamic
Results

34. Explain what is found in the All Objects report folder in SQL Developer
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
VALUES
99.99
Primary key/foreign key

35. List the reasons that a subquery could not be unnested.
X
Inconsistencies
Another null
ANSI

36. Which operator is most commonly used?
BETWEEN
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
UNION
4

37. When you run a script in SQL*Plus you must give the...
Results
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
Location of the file
Data

38. What is Oracle's most popular index storage structure?
SUM
TO_CHAR function
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.
B-Tree Index

39. Which one of the following string functions tells you how many characters are in a string?
Implicit conversion
LENGTH
UNION
Combine

40. SELECT * FROM instructor ORDER BY phone
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.
A correct statement
Structured Query Language
UNION operator

41. PAGESIZE
Business problems
Script
Default is 14; when you use the default - you repeat the heading every 14 rows.
RUN SCRIPT

42. FEEDBACK
Command returns the number of records returned by a query.
ANY
Multiple rows
DESC dict;

43. _________________ relationships are always optional relationships.
Recursive
SELECT DISTINCT menu FROM restaurant
ON
Re-create

44. A calculation with a null always yields...
Another null
+
2000
**** 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

45. _________ and __________ functions are opposites of each other and provide a value in a group of rows.
ANSI
Both MIN and MAX
X
Precision

46. To join four tables - you must have at least _____ join conditions.
Three
ROLLBACK
VALUES
Multiple rows

47. 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
USER_ - ALL_ - DBA_ - and V$
DICT_COLUMNS
+

48. To place a line comment in your SQL statements - you first place a // at the beginning of the line.
**** 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
FALSE
User-defined reports
Self-joins

49. Explain in detail the impact of INDEXES and how they are used by Oracle.
Multiple rows
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
Re-create

50. When using the following data: NUMBER(10 -4) - the # 10 is called the __________.
Equijoin and correlated subquery
Black
Precision
X