MySQL Database learning Note (i)-mysql introduction

1. Common sense:

MySQL is a small relational database management system, the developer of the Swedish MySQL AB company. was acquired by Sun Company on January 16, 2008. And in 2009, Sun was acquired by Oracle.

MySQL is an associated database management system that stores data in different tables rather than putting all of the data in a large warehouse. This increases speed and increases flexibility. MySQL's SQL "Structured Query Language". SQL is the most commonly used standardized language for accessing databases. The MySQL software uses the GPL (GNU General Public License). Because of its small size, fast speed, low total cost of ownership, especially the open source, many small and medium-sized web sites in order to reduce the total cost of ownership of the site chose MySQL as the site database.

Compared to other large databases such as Oracle, DB2, SQL Server, MySQL has its shortcomings, such as small size, limited functionality (MySQL cluster is relatively poor in functionality and efficiency), but this does not diminish its popularity.

Supports various operating systems such as AIX, FreeBSD, HP-UX, Linux, Mac OS, Novellnetware, OpenBSD, Os/2 Wrap, Solaris, Windows, and more.

2. mysql Storage engine:

　　MyISAM: MySQL's default database, most commonly used. Has a higher insert, query speed, but does not support transactions.

　　InnoDB: the preferred engine for transactional databases, supports acid transactions, and supports row-level locking.

　　BDB: Another option for transactional databases originating from Berkeley DB, supporting other transactional features such as commit and rollback.

　　Memory : All data is placed into the storage engine, which has very high insertion, update and query efficiency. However, it consumes a memory space that is proportional to the amount of data, and the content is lost when MySQL restarts.

　　Merge: combine a certain number of MyISAM tables into a single whole, which is useful for super-large data storage.

　　Archive: ideal for storing large amounts of independent data as historical records. Because they are not often read. Archive has an efficient insertion speed, but its support for queries is relatively poor.

　　Federated: combine different MySQL servers to logically make up a complete database. Ideal for distributed applications.

　　cluster/ndb: a highly redundant storage engine that provides services in conjunction with multiple data machines to improve overall performance and security. Suitable for applications with high data volumes, security and performance requirements.

　　CSV: A storage engine that logically divides data with commas.

blackhole: Black hole engine, any data written will disappear, generally used to record binlog do replication relay.

EXAMPLE: The storage Engine is a stub engine that doesn't do anything. It is intended as an example of MySQL source code to demonstrate how to start writing a new storage engine. Similarly, its main interest is to developers. The example storage engine does not support indexing.

Our most commonly used storage engine is InnoDB .

MySQL Database learning Note (i)-mysql introduction