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. The TIMESTAMP WITH LOCAL TIME ZONE data type allows...
Fractional seconds
Actual column
Implicit conversion
VALUES

2. ___________ subqueries allow you to reference columns from the outer query and execute the inner query repeatedly
CLOB
RIGHT LEFT JOIN
Correlated
Both MIN and MAX

3. Explain why constraints are used when building tables.

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4. Comparison operators can compare multiple _________________.
Committed
Columns
Hide data
LENGTH

5. The ____________ command makes changes permanent.
Script
Time zone
COMMIT
SUM

6. Joins involving multiple columns must always follow the ____________ relationship path.
CLOB
INNER JOIN
Primary key/foreign key
User-defined reports

7. What are the main components of a ROWID?
Nested
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.
F12
ANY

8. FEEDBACK
Command returns the number of records returned by a query.
Has not changed the name
All caps
Three

9. Self-joins are useful for performing comparisons and checking for ___________ in data.
Groups
Inconsistencies
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
Primary key/foreign key

10. Users can only see changes made to a database once they have been...
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
Committed
FALSE
ADD_MONTHS function

11. The _______ function lets you perform if-then-else functionality with the SQL language.
Equijoin and identical column names
NATURAL JOIN
DECODE
Equijoin

12. __________________ inserts the current date and time.
GROUP BY
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
SYSDATE
Time zone

13. What is the maximum value for a column defined as NUMBER(4 -2)?
The indexed column is part of an expression. In this case - consider creating a function-based index instead
99.99
ON
Asterisk

14. The ____________ icon allows you to execute multiple statements and emulates SQL *Plus as much as possible.
Same
RUN SCRIPT
99.99
ROLLBACK

15. Write a solution that adds 20 minutes to a given date.
Null
Location of the file
Logical unit of work
SELECT SYSDATE+1/96 - FROM dual

16. The using clause of the ANSI join syntax always assumes an...
Fractional seconds
Equijoin and identical column names
B-Tree Index
KEEP INDEX

17. What is the command you would type into SQL*Plus if you needed to know the definition for each column of a table?
Correlated
DICT_COLUMNS
VALUES clause of an INSERT statement
X

18. _________ rows are not allowed in the relational model.
SUM
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.
The way NULL values are treated
Orphan

19. It is considered good form to put all SQL commands in...
FALSE
Asterisk
All caps
Command returns the number of records returned by a query.

20. Explain the steps needed to run a script in SQL Developer
Nested
Non-matching rows
Inconsistencies
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.

21. When using the following data: NUMBER(10 -4) - the # 4 is called the __________.
Null
Scale
B-Tree Index
DD-MON-YY

22. When writing the syntax for finding information on three or more tables - the parenthesis around the ON clause is...
Another null
**** 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
Optional
Inconsistencies

23. Explain what a static data dictionary view is and how it is used
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.
Rounded edges
Equijoin
DD-MON-YY

24. 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
Twice
DECODE
Static or dynamic

25. If a graphical representation of a table's box has __________ it means that the relationship is identifying.
COMMIT
SYSDATE
Rounded edges
Structured Query Language

26. _________ and __________ functions are opposites of each other and provide a value in a group of rows.
SELECT DISTINCT menu FROM restaurant
Surrogate key
Both MIN and MAX
Equijoin

27. The query retrieves more than 5 to 15 percent of the 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
DICTIONARY
Self-joins
The indexed column is part of an expression. In this case - consider creating a function-based index instead

28. To equijoin a table with another table involves matching the...
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
Primary key/foreign key
Common column value

29. The ROWID pseudocolumn is not an ________- but it acts like one.
Multiple rows
Run scripts
Implicit conversion
Actual column

30. List the reasons that a subquery could not be unnested.
Semicolon or forward slash
KEEP INDEX
X
VALUES

31. The COUNT function is useful for determining whether a table has...
Multiple rows
Data
Retrieve
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.

32. The ___________ operator tests whether a matching row cannot be found.
Surrogate key
X
DECODE
Extra spaces

33. 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
ANSI
Has not changed the name
Combine

34. How many characters can be stored in the CHAR column/field?
DECODE
V$
2000
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.

35. What does the following function return? SELECT LENGTH(NULL) - FROM dual
Scale
Null
Surrogate key
DD-MON-YY

36. The purpose of the HAVING clause is to eliminate___________.
Groups
SET clause of an UPDATE statement
Business problems
ADD_MONTHS function

37. Explain what is found in the All Objects report folder in SQL Developer
Leading-edge
Equijoin and correlated subquery
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)

38. When disabling a unique or primary key - you can keep the index if you specify the __________________ clause in the ALTER TABLE statement.
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)
Common column value
KEEP INDEX
Black

39. A transaction is a...
Equijoin
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Non-matching rows
Logical unit of work

40. List the steps performed by a correlated subquery.
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
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
**** 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
Three

41. What is the name of the key automatically generated from a sequence?
Surrogate key
Mathematical equations
Leading-edge
Asterisk

42. Which operator is most commonly used?
Export Data
COMMIT
UNION
RIGHT LEFT JOIN

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

44. To revert back to a state that happened before you ran your change statement - you issue a ____________ command.
ROLLBACK
DROP INDEX need_to_pass_i
Self-joins
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

45. The ____________ clause on a CREATE TABLE statement can specify how much space to allocate.
Scalar
STORAGE
ADD
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT

46. When using the following data: NUMBER(10 -4) - the lowest number you can possibly have is __________.
Same
999999.9999
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
Three

47. A _____ is a query definition stored in the database that looks just like a table - but does not have any physical rows
STORAGE
Non-matching rows
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.
X

48. Another name for a data dictionary view is __________________ or _________________.
Static or dynamic
Primary key/foreign key
Details
Nested

49. The ____________ keywords and the USING clause of the ANSI join syntax are mutually exclusive.
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
NATURAL JOIN
Export Data
UTC

50. SQL Developer provides an extensive list of useful reports and offers the capability to create your own...
X
User-defined reports
+
ROLLBACK