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 _______ operator determines common rows.
Results
**** 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
INTERSECT
Optional

2. The time zone displacement value indicates the time difference from _______.
MINUS
NATURAL JOIN
UTC
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

3. The _______ function lets you perform if-then-else functionality with the SQL language.
Data
DECODE
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.
ROLLBACK

4. List 6 Table-Related Menu Choices
X
Equijoin and identical column names
RENAME - COPY - DROP - TRUNCATE - LOCK - & COMMENT
SET clause of an UPDATE statement

5. Explain how Oracle treats locks when a database is being updated and needs to be viewed by other users.
DECODE
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 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.
DICTIONARY

6. Which operator is most commonly used?
SUM
Mathematical equations
UNION
All

7. How many characters can you have using the VARCHAR data type?
4000
Leading-edge
Same
Static or dynamic

8. The query retrieves more than 5 to 15 percent of the rows
Any
Recursive
The indexed column is part of an expression. In this case - consider creating a function-based index instead
Month ddth - yyyy

9. What is the name of the key automatically generated from a sequence?
Primary key/foreign key
DECODE
Surrogate key
Default is 14; when you use the default - you repeat the heading every 14 rows.

10. The _____________ clause determines how rows are grouped.
GROUP BY
TO_CHAR function
IN ANY ALL SOME
DECODE

11. Explain in detail the impact of INDEXES and how they are used by Oracle.
Three
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
V$
DICT_COLUMNS

12. The using clause of the ANSI join syntax always assumes an...
BETWEEN
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
X
Equijoin and identical column names

13. A _________ subquery returns a single column with a single row
Scalar
When the table is small (unless your business rules require you too)
Static or dynamic
@ or START

14. A _____ is a query definition stored in the database that looks just like a table - but does not have any physical rows
X
Crow's foot
Parent table
Orphan

15. Self-joins are useful for performing comparisons and checking for ___________ in data.
Inconsistencies
Business problems
Testing functions
Self-joins

16. The DUAL table can be used for...
Testing functions
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.
Running a script file
ROLLBACK

17. Queries that are found in parentheses are done first - just as in the order of operations when doing...
User-defined reports
Equijoin and identical column names
Mathematical equations
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

18. Converting a text literal to DATE format requires the use of the...
Equijoin and correlated subquery
TO_CHAR function
2000
Fractional seconds

19. All SQL statements contained within a script must end with a _______________ - even if they are done in SQL Developer.
When the table is small (unless your business rules require you too)
NATURAL JOIN
Semicolon or forward slash
Multiple rows

20. When returning multiple rows - a subquery must contain the _____ - _____ - _____ - or ______ operator - otherwise Oracle will return an error
IN ANY ALL SOME
VALUES clause of an INSERT statement
X
Static or dynamic

21. Explain how Substitution Variables are used when writing scripts.
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.
Surrogate
The way NULL values are treated
UNION

22. The ____________ keywords and the USING clause of the ANSI join syntax are mutually exclusive.
Precision
ROLLBACK
NATURAL JOIN
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.

23. Explain how Dynamic SQL is used and give an example of a Dynamic SQL statement.
VALUES clause of an INSERT statement
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
INTERSECT
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.

24. The ________ operator cannot compare against a list of values.
RUN SCRIPT
X
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
LIKE

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

26. A calculation with a null always yields...
Another null
INNER JOIN
X
Testing functions

27. The ____________ icon allows you to execute multiple statements and emulates SQL *Plus as much as possible.
RUN SCRIPT
Twice
DICTIONARY
Time zone

28. What does the following function return? SELECT LENGTH(NULL) - FROM dual
Null
Self-joins
SYSDATE
Columns

29. FEEDBACK
ROLLBACK
Command returns the number of records returned by a query.
Common column value
When the table is small (unless your business rules require you too)

30. In a view you can give a column a different name than it has in the...
Non-matching rows
Parent table
Command returns the number of records returned by a query.
IN ANY ALL SOME

31. Explain what is found in the All Objects report folder in SQL Developer
Orphan
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.
99.99
MODIFY

32. The _______ function adds values together for a group of rows.
Mathematical equations
Self-joins
SUM
Extra spaces

33. If a graphical representation of a table's box has __________ it means that the relationship is identifying.
VALUES clause of an INSERT statement
Rounded edges
Both MIN and MAX
BETWEEN

34. A transaction is a...
Surrogate
A correct statement
Nested
Logical unit of work

35. SQL Developer's ____________________ option allows you to selectively export certain rows and columns.
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.
Export Data
RENAME just_two_more_weeks TO finally_i

36. Returns rows if the condition is true for all the values in the list
Default is 14; when you use the default - you repeat the heading every 14 rows.
TO_CHAR function
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.
All

37. How many characters can be stored in the CHAR column/field?
2000
Equijoin and correlated subquery
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
DESC dict;

38. SQL*Plus is used more than SQL Developer when you need to...
When the table is small (unless your business rules require you too)
UTC
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
Run scripts

39. What is the first column of a composite index called?
Leading-edge
B-Tree Index
Combine
X

40. _________________ relationships are always optional relationships.
Recursive
Business problems
99.99
**** 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

41. To revert back to a state that happened before you ran your change statement - you issue a ____________ command.
DECODE
BETWEEN
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.
ROLLBACK

42. _________ rows are not allowed in the relational model.
99.99
Orphan
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
Optional

43. What is the maximum value for a column defined as NUMBER(4 -2)?
Committed
@ or START
99.99
Hide data

44. The COUNT function is useful for determining whether a table has...
Data
SUM
Correlated
Optional

45. The ___________ operator tests whether a matching row cannot be found.
X
KEEP INDEX
ALL_OBJECTS
Primary key/foreign key

46. The data type definitions NUMBER(10) and NUMBER(10 -0) are the...
Same
Running a script file
Primary key/foreign key
User-defined reports

47. It is considered good form to put all SQL commands in...
All caps
DD-MON-YY
+
4

48. Users can only see changes made to a database once they have been...
CLOB
999999.9999
Static or dynamic
Committed

49. You use the __________ keyword to change characteristics of a column.
Asterisk
Hide data
Optional
MODIFY

50. What are the main components of a ROWID?
Mathematical equations
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.
Primary key/foreign key
ADD_MONTHS function