MySQL

MySQL is an open-source relational database management system (RDBMS). ... A relational database organizes data into one or more data tables in which data types may be related to each other; these relations help structure the data.

DML is short name of Data Manipulation Language which deals with data manipulation, and includes most common SQL statements such SELECT, INSERT, UPDATE, DELETE etc, and it is used to store, modify, retrieve, delete and update data in database.

Normalization is the process of efficiently organizing data in a database. There are two goals of the normalization process: eliminating redundant data (for example, storing the same data in more than one table) and ensuring data dependencies make sense (only storing related data in a table)

In a nutshell, SQL is a language for querying databases and MySQL is an open source database product. SQL is used for accessing, updating and maintaining data in a database and MySQL is an RDBMS that allows users to keep the data that exists in a database organized. So-called grouping sets specifications indicate on which expressions groupings must be performed. Not all SQL products support grouping sets. However, because many products, including MySQL, offer this feature, we discuss it here

With PHP, you can connect to and manipulate databases. MySQL is the most popular database system used with PHP.