Many dynamic websites require a back-end database. The database can contain information that the web pages display to the user, or the purpose of the database might be to store information provided by the user. In some applications, the database both provides available information and stores new information.
MySQL stores information in different formats. It allows different types of data to be used in different ways. The main types of data are character, numerical, and date and time. When you create a database, you tell MySQL what kind of data to expect in a particular column by using the MySQL names for data types.
MySQL is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter, and "SQL", the abbreviation for Structured Query Language. MySQL is a component of the LAMP open-source web application software stack. LAMP is an acronym for "Linux, Apache, MySQL, Perl/PHP/Python".
MariaDB is a community-developed fork of the MySQL relational database management system intended to remain free under the GNU GPL. Some of the original developers of MySQL forked it due to concerns over its acquisition by Oracle Corporation. Its lead developer is Michael "Monty" Widenius, one of the founders of MySQL AB. MariaDB is named after Monty's younger daughter Maria, similar to how MySQL is named after his other daughter My.
A FOREIGN KEY is a key used to link two tables together. It is a field (or collection of fields) in one table that refers to the Primary Key in another table. The table containing the foreign key is called the child table, and the table containing the candidate key is called the referenced or parent table.
In many cases, you often need to get data from multiple tables in a single query. You can use JOIN clause to get data from multiple tables in your single SQL query. A JOIN clause is used to combine rows from two or more tables, based on a related column between them.
The LIKE operator is used in a WHERE clause to search for a specified pattern in a column. There are two wildcards used in conjunction with the LIKE operator: