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 in detail the impact of INDEXES and how they are used by Oracle.
Results
Twice
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

2. What is the name of the key automatically generated from a sequence?
Re-create
Equijoin
Surrogate key
RUN SCRIPT

3. Explicit data type conversion is preferable to Oracle's...
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.
MINUS
X
Implicit conversion

4. The TRUNC function on a date without a format model truncates the timestamp to...
Surrogate
Correlated
12:00:00 A.M
Data

5. Which operator is most commonly used?
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.
UNION
V$
Implicit conversion

6. Which format mask displays December 31st - 1999?
Equijoin and identical column names
KEEP INDEX
99.99
Month ddth - yyyy

7. Explain the differences in how an ANSI Full Outer Join and a Full Outer Join using the UNION Operator work
X
Combine
Nested
SUM

8. SQL Developer's ____________________ option allows you to selectively export certain rows and columns.
Columns
UNION operator
Export Data
Retrieve

9. The ____________ clause on a CREATE TABLE statement can specify how much space to allocate.
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
STORAGE
User-defined reports
Optional

10. The RTRIM function is useful for eliminating ________ in a string.
MINUS
Extra spaces
Asterisk
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

11. List 4 aggregate functions
Orphan
Results
+
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)

12. You can simplify the writing of SQL statements by writing SQL _________ that generate and execute other SQL statements.
Script
Inconsistencies
ADD
BETWEEN

13. When using the following data: NUMBER(10 -4) - the lowest number you can possibly have is __________.
X
999999.9999
SYSDATE
NATURAL JOIN

14. The Nonequijoin can use the ________________ operator to construct joins that are not based on equality of values.
COMMIT
LIKE
BETWEEN
Precision

15. Users can only see changes made to a database once they have been...
Committed
The way NULL values are treated
Equijoin and identical column names
INNER JOIN

16. The term ____________ ___________ is used to express a join that satisfies the join condition.
INNER JOIN
LENGTH
MODIFY
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. When is it not a good idea to use an index?
F12
When the table is small (unless your business rules require you too)
Precision
Orphan

18. What is the main difference between the NOT EXISTS and the NOT IN operators?
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
The way NULL values are treated
Black
Both MIN and MAX

19. Another name for a data dictionary view is __________________ or _________________.
Optional
Static or dynamic
Equijoin
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.

20. Match each of the SQL commands on the left with a verb from the list.
@ or START
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
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
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

21. What do views do that makes them so useful for security?
Hide data
SET clause of an UPDATE statement
KEEP INDEX
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.

22. When you want to run a script in either SQL*Plus or SQL Developer - you can use a ______ or the _________ command.
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.
When the table is small (unless your business rules require you too)
4
@ or START

23. Explain how the SPOOL command is used and what program it can be used in.
Logical unit of work
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.
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
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

24. To restart a sequence at a lower number - you can drop and ________ the sequence.
Re-create
UNION
Asterisk
INNER JOIN

25. You use the _________ keyword to add columns or constraints to a table.
Static or dynamic
LENGTH
Leading-edge
ADD

26. Information that is returned after you run your statement are found in the __________ tab in SQL Developer.
X
Data
The way NULL values are treated
Results

27. What does SQL stand for?
Self-joins
Structured Query Language
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.
When the table is small (unless your business rules require you too)

28. 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
Groups
Recursive
Equijoin and correlated subquery

29. The COUNT function uses the __________ wildcard.
4
Asterisk
Logical unit of work
X

30. ___________ subqueries allow you to reference columns from the outer query and execute the inner query repeatedly
RIGHT LEFT JOIN
Correlated
INTERSECT
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)

31. The data type definitions NUMBER(10) and NUMBER(10 -0) are the...
KEEP INDEX
Any
DESC dict;
Same

32. The _____________ clause determines how rows are grouped.
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
INTERSECT
GROUP BY
Fractional seconds

33. Write an SQL statement for SQL *Plus in which you want any unique menu items to be displayed from the restaurant table
Business problems
ALL_OBJECTS
SELECT DISTINCT menu FROM restaurant
Re-create

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.
2000
Optional
Scalar
FALSE

35. It is considered good form to put all SQL commands in...
TO_CHAR function
Committed
Common column value
All caps

36. Explain why constraints are used when building tables.

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37. A join across three tables can be expressed with the ________ join syntax.
ANSI
KEEP INDEX
FALSE
BETWEEN

38. What is the most common DATE format found in SQL?
Mathematical equations
DD-MON-YY
Fractional seconds
**** 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

39. NUMBER functions can be...
Nested
Columns
STORAGE
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

40. Write the syntax to rename index just_two_more_weeks_i to finally_i
RIGHT LEFT JOIN
Crow's foot
RENAME just_two_more_weeks TO finally_i
12:00:00 A.M

41. Write a statement that drops the index need_to_pass_i
Export Data
Columns
DROP INDEX need_to_pass_i
Another null

42. It is always good practice to include the old values in the WHERE clause of UPDATE to ensure that another session or user _________________ in the meantime.
Has not changed the name
Same
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.
Business problems

43. Queries that are found in parentheses are done first - just as in the order of operations when doing...
Common column value
999999.9999
Mathematical equations
DESC dict;

44. When writing the syntax for finding information on three or more tables - the parenthesis around the ON clause is...
X
MINUS
Twice
Optional

45. The same function can be used ______ in a SELECT statement.
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.
Twice
Semicolon or forward slash
F12

46. When you have issued a DELETE command - you can still ________ those rows and restore the information.
VALUES clause of an INSERT statement
Retrieve
INNER JOIN
VALUES

47. The NEXTVAL and CURRVAL pseudocolumns can be used in which of the following SQL constructs? Select all that apply.
Any
VALUES clause of an INSERT statement
Default is 14; when you use the default - you repeat the heading every 14 rows.
RENAME just_two_more_weeks TO finally_i

48. You can use the ________________ to subtract months from a given date.
4000
TO_CHAR function
Nested
ADD_MONTHS function

49. A _____ is a query definition stored in the database that looks just like a table - but does not have any physical rows
RIGHT LEFT JOIN
BETWEEN
X
**** 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

50. Explain what a static data dictionary view is and how it is used
Optional
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.
Twice
FALSE