Database Interview Questions

• . What is database or database management systems (DBMS)?
• · What is SQL?
• · What’s difference between DBMS and RDBMS?
• · What are CODD rules?
• · What are E-R diagrams?
• · How many types of relationship exist in database designing? What is normalization? What are different type of normalization?
• · What is denormalization?
• · Can you explain Fourth Normal Form?
• · Can you explain Fifth Normal Form?
• · What’s the difference between Fourth and Fifth normal form?
• · Have you heard about sixth normal form?
• · What are DML and DDL statements?
• · How do we select distinct values from a table?
• · What is like operator for and what are wild cards?
• · Can you explain Insert, Update and Delete query?
• · What is order by clause?
• · What is the SQL In clause?
• · Can you explain the between clause?
• · I have an employee salary table how do we find the second highest from it?
• · What are different types of joins in SQL?
• · What is “CROSS JOIN”?
• · You want to select the first record in a given set of rows?
• · What is the default “SORT” order for a SQL?
• · What is a self-join?
• · What’s the difference between DELETE and TRUNCATE?
• · .What are Wildcard operators?
• · Twist: - What is like clause in SQL?
• · What’s the difference between “UNION” and “UNION ALL”?
• · What are cursors and what are the situations you will use them?
• · What are the steps to create a cursor?
• · What is “Group by” clause?
• · What is the difference between “HAVING” and “WHERE” clause?
• · What is a Sub-Query?
• · What are Aggregate and Scalar Functions?
• · Can you explain the SELECT INTO Statement?
• · What is a View?
• · What is “Correlated Sub queries”?
• · What is SQl injection?
• · What is “Data Warehousing”?
• · What are Data Marts?
• · What are Fact tables and Dimension Tables?
• · What is Dimensional Modeling?
• · What is Star Schema Design?
• · What is Snow Flake Schema design in database?
• · What’s the difference between Star and Snow flake schema?
• · What is ETL process in Data warehousing?
• · What are the different stages in “Data warehousing”?
• · What is “Data mining”?
• · Compare “Data mining” and “Data Warehousing”?
• · What are indexes?
• · What are B-Trees?
• · I have a table which has lot of inserts, is it a good database design to create
• indexes on that table?
• · Insert’s are slower on tables which have indexes, justify it?
• · Why do page splitting happen?
• · What are “Table Scan’s” and “Index Scan’s”?
• · What are the two types of indexes and explain them in detail?
• · What’s the difference between clustered and non-clustered indexes?

Best Of Luck