IT Interview Questions

1. What’s the difference between CHAR_LENGTH and LENGTH? - The first is, naturally, the character count. The second is byte count. For the Latin characters the numbers are the same, but they’re not the same for Unicode and other encodings.
2. How do you convert a string to UTF-8? - SELECT (techinterviews_question USING utf8);
3. What do % and _ mean inside LIKE statement? - % corresponds to 0 or more characters, _ is exactly one character.
4. What does + mean in REGEXP? - At least one character. Appendix G. Regular Expressions from MySQL manual is worth perusing before the interview.

1. Explain MySQL architecture. - The front layer takes care of network connections and security authentications, the middle layer does the SQL query parsing, and then the query is handled off to the storage engine. A storage engine could be either a default one supplied with MySQL (MyISAM) or a commercial one supplied by a third-party vendor (ScaleDB, InnoDB, etc.)
2. Explain MySQL locks. - Table-level locks allow the user to lock the entire table, page-level locks allow locking of certain portions of the tables (those portions are referred to as tables), row-level locks are the most granular and allow locking of specific rows.

1. To test a Web Service you must create a windows application or web application to consume this service? It is True/False?
2. How many classes can a single.NET DLL contain?
3. What are good ADO.NET object(s) to replace the ADO Recordset object?
4. On order to get assembly info which namespace we should import?
5. How do you declare a static variable and what is its lifetime? Give an example.
6. How do you get records number from 5 to 15 in a dataset of 100 records? Write code.

1. What is scrollable cursor?
2. The use of HAVING, WHERE and GROUPBY in one SQL?
3. What is SORTING and GROUPING?
4. What are the different types of OUTER JOINS?
5. Explain the UNION operation in SQL . What is meant by OUTER JOIN?
6. What is a non-correlated subquery?
7. What is a correlated subquery?
8. What do you know about subqueries?
9. What is the theory behind the JOIN statement in DB2?
10. What are the different types of SQL?
11. How to drop the column in a table?
12. How to drop the index?

1. What are the differences between database designing and database modeling?
2. If the large table contains thousands of records and the application is accessing 35% of the table, which method do you use: index searching or full table scan?
3. In which situation whether peak time or off peak time you will execute the ANALYZE TABLE command. Why?
4. How to check to memory gap once the SGA is started in Restricted mode?
5. All the users are complaining that their application is hanging. How you will resolve this situation in OLTP?