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. A _________ subquery returns a single column with a single row
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.
Month ddth - yyyy
Surrogate
Scalar

2. You use the _________ keyword to add columns or constraints to a table.
ADD
The indexed column is part of an expression. In this case - consider creating a function-based index instead
User-defined reports
Primary key/foreign key

3. The using clause of the ANSI join syntax always assumes an...
Scale
Correlated
Equijoin and identical column names
Equijoin and correlated subquery

4. When is it not a good idea to use an index?
Inconsistencies
SET clause of an UPDATE statement
When the table is small (unless your business rules require you too)
LIKE

5. How many characters can be stored in the CHAR column/field?
IN ANY ALL SOME
ANSI
@ or START
2000

6. What is the keyboard shortcut for the ROLLBACK command?
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
F12
GROUP BY
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)

7. What is the Oracle data dictionary called that contains a set of tables and views containing the data about the database?
DICTIONARY
Black
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.
ALL_OBJECTS

8. To restart a sequence at a lower number - you can drop and ________ the sequence.
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.
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
Non-matching rows
Re-create

9. 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.
VALUES
INNER JOIN
Mathematical equations
MINUS

10. When column names on the tables are different - you use the ______ condition.
Same
Running a script file
TO_CHAR function
ON

11. Another name for a data dictionary view is __________________ or _________________.
INNER JOIN
Static or dynamic
Hide data
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.

12. Joins involving multiple columns must always follow the ____________ relationship path.
Recursive
Primary key/foreign key
RENAME just_two_more_weeks TO finally_i
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.

13. Write the syntax to rename index just_two_more_weeks_i to finally_i
Static or dynamic
Business problems
ANY
RENAME just_two_more_weeks TO finally_i

14. When you run a script in SQL*Plus you must give the...
Location of the file
BETWEEN
12:00:00 A.M
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

15. Explain how the SPOOL command is used and what program it can be used in.
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
Running a script file
Both MIN and MAX
MINUS

16. Which operator is most commonly used?
INNER JOIN
TO_CHAR function
UNION
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

17. __________________ inserts the current date and time.
Inconsistencies
Mathematical equations
ANY
SYSDATE

18. The ________________ is a type of statement whereby you retrieve data that exists in one table - but not in another.
Nested
INTERSECT
MINUS
Rounded edges

19. Explain the steps needed to run a script in SQL Developer
Script
Default is 14; when you use the default - you repeat the heading every 14 rows.
UNION
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.

20. The DUAL table can be used for...
Scale
X
Testing functions
UNION

21. The _______ function adds values together for a group of rows.
SUM
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Fractional seconds
RENAME just_two_more_weeks TO finally_i

22. If a graphical representation of a table's box has __________ it means that the relationship is identifying.
Rounded edges
Retrieve
Orphan
Export Data

23. Instead of using the Oracle Outer Join Operator or the ANSI syntax - you can achieve the same result with two SQL statements: ____________ and a ____________
Month ddth - yyyy
RIGHT LEFT JOIN
Equijoin and correlated subquery
Mathematical equations

24. Explicit data type conversion is preferable to Oracle's...
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
Parent table
UNION
Implicit conversion

25. What is the name of the key automatically generated from a sequence?
Surrogate key
Self-joins
Non-matching rows
2000

26. A calculation with a null always yields...
Parent table
Committed
Another null
DECODE

27. What is the data type you can use if you need an unlimited number of textual characters?
4000
Equijoin
Testing functions
CLOB

28. When using the following data: NUMBER(10 -4) - the lowest number you can possibly have is __________.
Correlated
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.
**** 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
999999.9999

29. PAGESIZE
Default is 14; when you use the default - you repeat the heading every 14 rows.
Any
VALUES
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.

30. UNION ALL does not sort - therefore it is less time consuming to use than the...
Actual column
ALL_OBJECTS
Hide data
UNION operator

31. The __________ operator is inclusive of the two values specified.
Another null
Twice
Month ddth - yyyy
BETWEEN

32. What is Oracle's most popular index storage structure?
B-Tree Index
SUM
Combine
Null

33. The _______ operator determines common rows.
Leading-edge
INTERSECT
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.
RENAME just_two_more_weeks TO finally_i

34. 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.
Equijoin and correlated subquery
FALSE
CLOB
RENAME just_two_more_weeks TO finally_i

35. Explain why constraints are used when building tables.

36. When you want to run a script in either SQL*Plus or SQL Developer - you can use a ______ or the _________ command.
Committed
@ or START
RENAME just_two_more_weeks TO finally_i
Primary key/foreign key

37. The ___________ operator tests whether a matching row cannot be found.
RIGHT LEFT JOIN
LIKE
X
999999.9999

38. When using the data NUMBER(10 -4) there will be _______ digits following the decimal point.
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.
RIGHT LEFT JOIN
STORAGE
4

39. Explain how Dynamic SQL is used and give an example of a Dynamic SQL statement.
RENAME just_two_more_weeks TO finally_i
Mathematical equations
Time zone
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.

40. List the reasons that a subquery could not be unnested.
X
Rounded edges
MINUS
Correlated

41. Users can only see changes made to a database once they have been...
Committed
Any
Static or dynamic
INNER JOIN

42. Explain what a static data dictionary view is and how it is used
Columns
MINUS
DD-MON-YY
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.

43. When disabling a unique or primary key - you can keep the index if you specify the __________________ clause in the ALTER TABLE statement.
X
Equijoin and correlated subquery
KEEP INDEX
Business problems

44. 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
Combine
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
Mathematical equations

45. FEEDBACK
Command returns the number of records returned by a query.
All
Time zone
Scale

46. A transaction is a...
INNER JOIN
Logical unit of work
Static or dynamic
FALSE

47. SQL Developer's ____________________ option allows you to selectively export certain rows and columns.
MODIFY
Correlated
ANY
Export Data

48. What does the following function return? SELECT LENGTH(NULL) - FROM dual
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.
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)
Null
Export Data

49. To join four tables - you must have at least _____ join conditions.
Three
Extra spaces
12:00:00 A.M
RUN SCRIPT

50. Comparison operators can compare multiple _________________.
Columns
Leading-edge
KEEP INDEX
SET clause of an UPDATE statement