Wednesday 13 June 2018

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

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