8 Important DBMS Interview Questions for techies
Congratulations on reaching the interview stage. It's surely a great achievement to get here as it is a testament to the fact that you have met the organisation's key selection requirements. However, don't rest on your laurels just yet. A DBMS job interview gives you the chance to convince your future employer that you’re the right fit for the position. One sure-shot way to succeed is to prepare really well for the interview.
Here we list eight essential DBMS interview questions to help you in your next interview.
1. Can you explain two key differences between DBMS and RDBMS?
• While DBMS store data as files, RDBMS on the other hand, stores data in a tabular form while also providing relationship integrity.
• The concept of normalisation doesn't exist in DBMS while it's present in RDBMS.
2. Can you point out how many types of database languages exist?
There are essentially four types of database languages:
• Data Definition Language (DDL)
• Data Manipulation Language (DML)
• DATA Control Language (DCL)
• Transaction Control Language (TCL)
3. Can you explain the integrity rules in DBMS?
There are two primary integrity rules that exist in DBMS:
• Entity Integrity: It states that "Primary key can never have a NULL value."
• Referential Integrity: It specifies that "The value of a Foreign Key can either be a NULL value or should be the primary key value of any other relation.”
4. Can you describe what BCNF is in the DBMS?
BCNF stands for the Boyce Codd Normal Form. Considered to be an advanced form of 3NF, BCNF is stricter than the 3NF. At times, it’s also called as 3.5NF.
In addition, any table is said to comply with BCNF if it satisfies the following two conditions:
• If it is in the 3NF.
• For every functional dependency X->Y, where X is the super key of a table.
5. Can you describe the different phases of a Transaction?
Every transaction has three different phases:
• Analysis phase
• Redo phase
• Undo phase
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6. Can you list out the different types of keys?
There are seven types of keys available.
• Primary key
• Candidate key
• Super key
• Alternate Key
• Unique Key
• Composite/Compound Key
• Foreign key
7. Can you touch upon the different type of relationships that exist in DBMS?
DBMS relationships are used to portray an association between the tables. The various relationship types are as under:
8. Can you list out the various levels of data abstraction?
There are three levels of data abstraction:
• Physical level: Considered to be the lowest level of abstraction, this level explains the storage of data.
• Logical level: The next level of abstraction, this level explains the contents of the data that is stored in the database as well as describing the relationship between them.
• View level: Considered to be the highest level of data abstraction, this level only describes a part of the entire database.
We want to ensure you go in fully prepared for your DBMS interview leaving nothing to chance. Hence, we have compiled an additional list of eight frequently asked DBMS Interview questions that will surely leave you in a position of strength before your all-important DBMS interview.
• Explain the concept of data abstraction in DBMS
• Can you touch upon the concept of the functionality of DML Compiler?
• Can you explain what durability means in DBMS?
• What does transparent DBMS mean?
• What does data warehousing mean?
• What is 1NF, 2NF, and 3NF?
• Explain what a stored procedure is
• Describe the communication process with RDBMS?
Before going in for that crucial DBMS interview, make it a point to review the answers you have prepared. While you’re at it, try and figure out new innovative ways to showcase your skills and experience to your prospective employer as well. Sometimes all it needs to crack an interview is to try a different approach.
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