database
Data is actually describe things features a set of symbols, refer to the database is stored data warehouse.
Based on what we learned before, in order to permanently stored data, are stored in a file, without a doubt, a file only can only exist on a single machine.
In the software development process, all the components of the program can not only run on one machine, the machine if this operation fails the collapse of the entire software means, and the program execution efficiency depends on the hardware carrying it, performance of a machine and the machine is always limited.
Thus, different components of the program should be run on different machines, and also spare the machine, if one of the machines fails, the standby machine can quickly take over, to ensure the stability of running.
And now, my program to run on different machines, to read the file, then how to do? The total does not work on all machines are required to file a copy of it, I will not speak a waste of hard disk resource, if I were a machine on which you want to make changes to a file, then all the machines must be synchronized to make changes, it is more trouble a.
Based on this demand, we can call a special data storage machines, all the files needed to run are placed on the machine, other machines when needed, can be obtained through socket communication or alteration.
Okay, now have such a machine, then we need to develop a client socket file data communication systems on other machines running server and run a set of data stored on the machine.
Such a system, many issues to consider, for example, different machines to access the same file at the same time need to consider file locking, data files that may exist between different relations should be how to integrate, and that different people developed system is certainly not Like, I could get the file contents get expressed, but others may get the file contents using wget.
A series of problems, caused a lot of confusion, a database developed by different people mess, finally, finally there is a stand out, y'all Knock it off, I developed a database system is perfect, you are directly I do not use on the line, I promise to you to safeguard data.
Because of its database management software to do really perfect, it also received, so MySQL was born.
Conceptual understanding
Database server: database management software running
Database Management Software: Database Management
Database: the folder to organize your files / tables
Table: the file used to store a multi-line / multiple records
Record: a plurality of information fields composed of a record, that line in the file content