引言：最近“数据库引擎”这个字眼一直出现，学了这么久的数据库竟然不知道“数据库引擎”为何物，哎~~google了一下，顺便牵出一些其他东西，整理如下。
“数据库引擎就是驱动各种数据库的程序，它负责处理数据库相关工作的整个核心部份。同样的，数据库应用项目的操作指令，均会通过数据库引擎的处理作用到数据库上。”
注意：“数据库引擎”一般是针对开源DBMS，如MySQL来说的，在Oracle上也是有存储引擎的，但Oracle官方从来都不这么提，只说存储架构。按功能上来看，InnoDB在设计之初参考了Oracle的设计（如表空间，extent，块等）。
以下是来自维基百科的解释：
database engine
A database engine (or "storage engine") is the underlying software component that a database management system (DBMS) uses to create, read, update and delete(CRUD) data from a database. Most database management systems include their own application programming interface (API) that allows the user to interact with their underlying engine without going through the user interface of the DBMS.
The term database engine is frequently used interchangeably with database server or database management system.
Many of the modern DBMS support multiple storage engines within the same database. For example, MySQL supports InnoDB as well as MyISAM.
Some storage engines are transactional.
| Name | Free | Transactional |
|---|---|---|
| Aria | GPL | No |
| BlitzDB | GPL | No |
| Falcon | GPL | Yes |
| InnoDB | GPL | Yes |
| MyISAM | GPL | No |
| InfiniDB | CPL | No |
| TokuDB | N/A | Yes |
| XtraDB | GPL | Yes |
InnoDB
InnoDB is the default storage engine for MySQL as of MySQL 5.5. It provides the standard ACID-compliant(ACID:Atomicity, Consistency, Isolation, Durability)transactionfeatures, along with foreign key support (Declarative Referential Integrity). It is included as standard in most binariesdistributed by MySQL AB, the exception being some OEM versions.
InnoDB became a product of Oracle Corporation after its acquisition of Innobase Oy in October 2005.[1] The software isdual licensed; it is distributed under the GNU General Public License, but can also be licensed to parties wishing to combine InnoDB in proprietary software.
Innobase
Innobase Oy is a Finnish company headquartered in Helsinki, Finland. Innobase is best known for being the developer of InnoDB transactional storage engine for the MySQL open source database system. Innobase Oy is a subsidiary of Oracle Corporation, which acquired Innobase in 2005.
MySQL AB
MySQL AB was a software company that was founded in 1995 but acquired by Sun Microsystems in 2008 which was then, in 2010, acquired by Oracle Corporation. MySQL AB is the creator of MySQL, a relational database management system, as well as related products such as MySQL Cluster.