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database engine
The database engine is the core service for storing, processing, and protecting data
. Utilize the database engine to control access rights and process transactions quickly, meeting the requirements of most data-intensive applications in the enterprise. Use the database engine to
create
relational databases for online transaction processing or online analytical processing data. This includes creating tables for storing data and database objects (such as indexes, views, and stored procedures )
for
viewing, managing, and securing data . You can use SQL Server Management Studio to manage database objects and use SQL Server Profiler to capture server events.
In the database engine documentation, the order of topics
follows
the main sequence of tasks for implementing a system for data storage using the database engine.
● Design and create a database to hold the relational tables or XML documents required by the system.
• Implement a system to access and change data stored in the database. This includes implementing Web sites or applications that consume data, as well as generating processes that use SQL Server tools and utilities to consume data.
● Implemented systems are deployed for units or clients.
●Provide day-to-day management support to optimize database performance.
The database engine you can use depends on how mysql was compiled when it was installed. To add a new engine, MYSQL must be recompiled. By default, MYSQL supports three engines: ISAM, MYISAM and HEAP. Two other types, INNODB and BERKLEY (BDB), are also often available.
ISAM
ISAM is a well-defined and time-tested approach to managing data tables, designed with the database being queried far more often than it is being updated. As a result, ISAM performs read operations very fast and does not consume a lot of memory and storage resources. The two main drawbacks of ISAM are that it doesn't support transactions, and it's not fault-tolerant: if your hard drive crashes, the data files can't be recovered. If you are using ISAM in a mission critical application, it is necessary to back up all your real-time data frequently, and MYSQL can support such a backup application through its replication feature.
MYISAM
MYISAM is the ISAM extension format of MYSQL and the default database engine. In addition to providing a large number of functions for index and field management not found in ISAM, MYISAM also uses a table locking mechanism to optimize multiple concurrent read and write operations. The price is that you need to run the OPTIMIZE TABLE command frequently to recover the space wasted by the update mechanism. MYISAM also has some useful extensions, such as the MYISAMCHK tool to repair
database
files and the MYISAMPACK tool to recover wasted space.
MYISAM emphasizes fast read operations, which may be the main reason why MYSQL is so favored by web development: in web development, a lot of data operations you perform are read operations. Therefore, most
web
hosting providers and Internet platform providers only allow the MYISAM format.
HEAP
HEAP allows temporary tables that only reside in memory. Residing in memory makes HEAP faster than both ISAM and MYISAM, but the data it manages is volatile and all data is lost if not saved before shutdown. HEAP also doesn't waste a lot of space when rows are deleted. HEAP tables are useful when you need to use SELECT
expressions to select and manipulate data.
Remember to delete the form when you are done using it.
INNODB和BERKLEYDB
Both the INNODB and BERKLEYDB (BDB) database engines are direct products of the technology that enables MYSQL's flexibility, the MYSQL++ API. Almost every challenge you face when using MYSQL stems from the fact that ISAM and the MYISAM database engine do not support transactions nor foreign keys. Although much slower than the ISAM and MYISAM engines, INNODB and BDB include support for
transactions
and foreign keys, both of which were absent from the first two engines. As mentioned earlier, if your design requires one or both of these features, you are forced to use one of the latter two engines.
Reprinted in: https://www.cnblogs.com/whnbky/p/11557479.html