Linux and GNU: Linux is the operating system kernel (not a complete system), running on top of the many GNU programs (GUN program now runs not only on Linux environment, the UNIN / Windows also have), they are a combination of a set of common available system. FSF (Free Software Foundation, the Free Software Foundation) will this combination is defined as GNU / Linux, named controversial, some Linux distributions using the "GNU / Linux" argument, more companies and developers using the "Linux . "
Free Software: Must open source, can be free to use, free to reproduce, study, modify and distribute.
MySQL basic description:
MySQL currently belong to Oracle Oracle, MySQL called relational database, Microsoft's SQL Server.
MySQL database support can run on multiple operating systems, including Solaris, Mac OS, FreeBSD and Windows, Linux all support.
The number of core function is to process the data, which provide space for data storage is one of its main main functions.
Generally not directly to the database data storage, to store a table / index such objects completed.
MySQL tables are based on the object database maintenance, that is part of a library table, library table.
Oracle objects in the table is based on the user, create a user belongs to all the objects in the user table.
MySQL database is composed of multiple databases (once it is created, by default there are at least four).
Oracle in the database as a whole.
When the default configured set of MySQL database server, the system will default to create four libraries:
(1) information_schema: user records, tables, views, and other metadata information. It is out of the virtual library is created and maintained by the MySQL instance, the objects are stored in memory (can not find the corresponding physical presence on the disk, because it is virtual), users can not create objects in the library , root user can not. For the sole user of the library can do is query.
(2) mysql: user rights record, help, log and other information.
(3) performance_schema: MySQL database service performance indicators.
(4) test: test library.