Update README.md

Author: NgoTheHieu

README.md

@@ -10,8 +10,19 @@
 
 
 #### Q. ***What are indexes in a Database? What are the types of indexes***
+An index is a database structure that you can use to improve the performance of database activity. A database table can have one or more indexes associated with it. An index is defined by a field expression that you specify when you create the index. Typically, the field expression is a single field name, like EMP_ID.
+
 #### Q. ***What are the different tables present in MySQL***
+Note that MySQL supports two different kinds of tables: transaction-safe tables (InnoDB and BDB) and non-transaction-safe tables (HEAP, ISAM, MERGE, and MyISAM). Advantages of transaction-safe tables (TST): Safer.
 #### Q. ***What are the technical features of MySQL*** 
+Relational Database Management System (RDBMS) MySQL is a relational database management system. ...
+Easy to use. MySQL is easy to use. ...
+It is secure. ...
+Client/ Server Architecture. ...
+Free to download. ...
+It is scalable. ...
+Speed. ...
+High Flexibility.
 #### Q. ***Explain SELECT, LIKE, IN, Regular-Expression, Datatypes, Sub-Query in mySQL***
 #### Q. ***Explain JOIN Query in mySQL***
 #### Q. ***Explain Stored Procedure, View, Event, triggers in mySQL***