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. If a graphical representation of a table's box has __________ it means that the relationship is identifying.
Rounded edges
COMMIT
FALSE
Command determines the total number of characters SQL *Plus displays in on line before beginning a new line.

2. Explain how Oracle treats locks when a database is being updated and needs to be viewed by other users.
**** 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
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
Scale
Non-matching rows

3. A join across three tables can be expressed with the ________ join syntax.
Month ddth - yyyy
SYSDATE
ANSI
MODIFY

4. _________ rows are not allowed in the relational model.
+
Equijoin and correlated subquery
Any
Orphan

5. The __________ operator is inclusive of the two values specified.
NATURAL JOIN
99.99
BETWEEN
Data

6. ____________ are useful for analyzing and exploring the relationships within your data
Logical unit of work
12:00:00 A.M
ALL_OBJECTS
Self-joins

7. You can use the ________________ to subtract months from a given date.
Nested
MODIFY
ADD_MONTHS function
Lists all objects accessible for the chosen database connection. Also lists a helpful dependencies report for accessing change impact.

8. Explain why constraints are used when building tables.

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9. The NEXTVAL and CURRVAL pseudocolumns can be used in which of the following SQL constructs? Select all that apply.
VALUES clause of an INSERT statement
X
Rounded edges
Any

10. Explain what a static data dictionary view is and how it is 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.
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.
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.
Committed

11. To place a line comment in your SQL statements - you first place a // at the beginning of the line.
Common column value
FALSE
999999.9999
12:00:00 A.M

12. When is it not a good idea to use an index?
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
INTERSECT
USER_ - ALL_ - DBA_ - and V$
When the table is small (unless your business rules require you too)

13. To join four tables - you must have at least _____ join conditions.
Non-matching rows
Script
Common column value
Three

14. List 4 aggregate functions
Black
COUNT(registration_date) - AVG (capacity) - MIN (capacity) - MAX (capacity)
Semicolon or forward slash
RUN SCRIPT

15. Self-joins are useful for performing comparisons and checking for ___________ in data.
FALSE
Inconsistencies
Null
DECODE

16. To equijoin a table with another table involves matching the...
Testing functions
Multiple rows
SUM
Common column value

17. To restart a sequence at a lower number - you can drop and ________ the sequence.
INNER JOIN
DD-MON-YY
Re-create
Combine

18. The same function can be used ______ in a SELECT statement.
Twice
Fractional seconds
MODIFY
Extra spaces

19. The data type definitions NUMBER(10) and NUMBER(10 -0) are the...
Data
99.99
Asterisk
Same

20. In SQL Developer field names and table names are shown in the color _______.
SUM
Black
Equijoin and correlated subquery
B-Tree Index

21. How many characters can you have using the VARCHAR data type?
Run scripts
DD-MON-YY
4000
Running a script file

22. The ____________ command makes changes permanent.
Orphan
Scalar
COMMIT
MODIFY

23. Queries that are found in parentheses are done first - just as in the order of operations when doing...
Export Data
Precision
Mathematical equations
Crow's foot

24. The ALTER SESSION statement can change the session's...
+
LENGTH
Time zone
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.

25. The query retrieves more than 5 to 15 percent of the rows
Nested
X
MODIFY
The indexed column is part of an expression. In this case - consider creating a function-based index instead

26. What do views do that makes them so useful for security?
Location of the file
Running a script file
Hide data
Retrieve

27. What are the main components of a ROWID?
F12
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.
Has not changed the name
Equijoin and identical column names

28. _________ and __________ functions are opposites of each other and provide a value in a group of 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.
MINUS
99.99
Both MIN and MAX

29. What is the most common DATE format found in SQL?
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.
Control - Revoke - Define - TRUNCATE Manipulate - MERGE
DD-MON-YY
Location of the file

30. What is the maximum value for a column defined as NUMBER(4 -2)?
Correlated
Location of the file
X
99.99

31. You use the __________ keyword to change characteristics of a column.
Optional
Three
MODIFY
Any

32. When column names on the tables are different - you use the ______ condition.
Equijoin and identical column names
Scalar
ON
Correlated

33. What is the name of the key automatically generated from a sequence?
Surrogate key
The way NULL values are treated
COMMIT
KEEP INDEX

34. Write a solution that adds 20 minutes to a given date.
SELECT SYSDATE+1/96 - FROM dual
UTC
Non-matching rows
DICTIONARY

35. Write the syntax to rename index just_two_more_weeks_i to finally_i
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.
RENAME just_two_more_weeks TO finally_i
Structured Query Language
X

36. Which operator is most commonly used?
UNION
X
RENAME just_two_more_weeks TO finally_i
LIKE

37. The focus of the logical data model is _____________
ANSI
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.
Any
Business problems

38. The RTRIM function is useful for eliminating ________ in a string.
Running a script file
TO_CHAR function
Extra spaces
Committed

39. __________________ inserts the current date and time.
Running a script file
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
SYSDATE
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.

40. What is the main difference between the NOT EXISTS and the NOT IN operators?
Committed
The way NULL values are treated
VALUES
DECODE

41. _________________ relationships are always optional relationships.
Retrieve
Recursive
BETWEEN
Equijoin

42. What does SQL stand for?
SUM
Semicolon or forward slash
Structured Query Language
USER_ - ALL_ - DBA_ - and V$

43. The _______ function adds values together for a group of rows.
INNER JOIN
Columns
SUM
Script

44. Returns rows if the condition is true for all the values in the list
Dynamic SQL is used to be continuously updated by the background processes in the Oracle instance but never by the user.
All
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
X

45. Subqueries can return...
**** 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
MINUS
Multiple rows
DICTIONARY

46. Which one of the following string functions tells you how many characters are in a string?
@ or START
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
The way NULL values are treated
LENGTH

47. The ________________ is a type of statement whereby you retrieve data that exists in one table - but not in another.
UNION operator
MINUS
NATURAL JOIN
DECODE

48. To revert back to a state that happened before you ran your change statement - you issue a ____________ command.
2000
Semicolon or forward slash
LENGTH
ROLLBACK

49. Comparison operators can compare multiple _________________.
Parent table
Columns
Scale
FALSE

50. The Nonequijoin can use the ________________ operator to construct joins that are not based on equality of values.
Testing functions
All caps
BETWEEN
999999.9999