Prime 20 Oracle Database Interview Questions with Solutions for 3 to five Years Skilled

1. What’s the distinction between Varchar and Varchar2? (reply)
Reply:
Varchar can retailer characters as much as 2000 bytes whereas Varchar2 can retailer
characters as much as 4000 bytes. Varchar holds unused area whereas Varchar2
releases unused area.

2. Identify the varied Oracle database objects
Reply: tables, tablespaces, views, indexes, and synonyms.

3. What’s the work of RAW datatype in Oracle?
Reply: RAW datatype is used to retailer variable-length binary information or byte string values.

4. What’s using Combination capabilities in Oracle? (reply)
Reply:
In Oracle, an combination operate is outlined as a operate the place values
of a number of rows or data are joined collectively to get a single worth
output. There are some frequent Combination capabilities that are: Common,
Rely, and Sum.

5. What’s an Oracle desk?
Reply:
A desk as outlined in Oracle, is a primary unit of knowledge storage within the
Oracle database. A desk comprises data in rows and columns.

6. What’s a view? (reply)
Reply: A view is outlined as a logical desk that’s primarily based on a number of tables or views.

7. Which language has been used to develop Oracle?
Reply: Oracle has been developed utilizing C Language.

8. What’s a nested desk?
Reply: A nested desk is a knowledge sort present in Oracle and is used to assist columns containing multi-valued attributes.

9. What’s BLOB datatype?
Reply: A BLOB information sort is a various size binary string that’s used to retailer two gigabytes of reminiscence.

10. What the distinction is between TRANSLATE and REPLACE?
Reply: Translate is used for character by character substitution whereas Substitute is used to substitute a single character with a phrase.

11. What’s Merge Assertion used for?
Reply:
A merge assertion is used to pick out rows from a number of information sources
for updating and insertion right into a desk or a view. In easy phrases, you
can say it’s used to mix a number of operations.

12. What are the temporal information sorts in Oracle?
Reply: Oracle has three temporal information sorts that are as follows;

• Date Knowledge Kind – Totally different codecs of Dates
• TimeStamp Knowledge Kind – Totally different codecs of Time Stamp
• Interval Knowledge Kind – Interval between dates and time

13. Within the Oracle model 9.3.0.5.0, what does every quantity present?
Reply:

• 9- Main database launch quantity
• 3- Database upkeep launch quantity
• 0-Utility server launch quantity
• 5- Element Particular launch quantity
• 0-Platform Particular launch quantity

14. What’s bulk copy or BCP in Oracle?
Reply:
in Oracle, bulk copy or BCP is used to import or export information from
tables and views however it doesn’t copy the construction of the identical information.

15. What’s the distinction between a sizzling backup and a chilly backup?
Reply:
sizzling backup is known as a web-based backup since it’s executed when the
database continues to be lively whereas a chilly backup is known as an
offline backup as a result of it’s executed when the database has been shut down.

16. What’s a Be a part of used for? What are the kinds of Joins utilized in SUBQUERIES?
Reply:
a be a part of is mainly used to mix and evaluate particular rows of knowledge
from two or much more tables in a database. Forms of joins are as
follows:

17. What are the attributes of cursor?
Reply: cursor has the next attributes:

• %FOUND
  – this has three capabilities that are: returning NULL if cursor is open
  and fetch has not been executed, returning False if no rows are returned
  and at last returning TRUE if the fetch of cursor is executed
  efficiently.
• %NOT FOUND – this one too performs three
  capabilities: it returns True if no row was returned, it returns False if
  fetch has been executed and at last it returns NULL if cursor is open
  and fetch has not been executed.
• %ISOPEN – this one returns true if the cursor is open and likewise returns false if the cursor is closed.
• %ROWCOUNT – this one returns the variety of rows fetched.

18. What are the completely different constraints utilized in Oracle?
Reply:

• NOT NULL – signifies {that a} explicit column can’t comprise NULL values.
• NULL – signifies {that a} explicit column can comprise NULL values.
• DEFAULT – signifies the worth is assigned to default worth.
• CHECK – this one validates that values in a given column meet the particular standards.

19. What’s Integrity Constraint?
Reply:
Integrity Constraint is outlined as a declaration that defines a
enterprise rule for a desk. Widespread kinds of Integrity Constraints are
Area Integrity and Referential Integrity.

20. What are the kinds of synonyms?
Reply: there are two kinds of synonyms specifically:

• Non-public – this will solely be accessed by the proprietor.
• Public – this one shouldn’t be restricted and it may be accessed by any database consumer.

That is all concerning the continuously requested Oracle database interview questions for 3 to five years skilled professionals. You should utilize these inquiries to shortly revise the important thing Oracle ideas earlier than going for interview. In
conclusion, I can confidently say that the above talked about questions
are updated and are the questions that you’ll meet throughout your
Oracle interview. 

In case you undergo them keenly and perceive all of
them I promise you that you should have an easy time through the
interview and you’ll even ensure of getting the job.

That is
the true deal for you. Undergo these questions time and again
and you’ll finally grasp all the things and you’ll be good to go.
Your confidence will enhance and you’ll now see issues in a special
perspective. At all times do not forget that preparations is essential in any
sort of interview. I want you the most effective of luck.