1. 创建数据库 CREATE DATABASE语法: CREATE DATABASE database_name [ ON [ PRIMARY ] filespec [ ,...n ] [ , filegroup [ ,...n ] ] [ LOG ON filespec [ ,...n ] ] ] [ COLLATE collation_name ] filespec :: = {( NAME = logical_file_name , FILENAME
1. 创建数据库
CREATE DATABASE语法:
<span>CREATE</span> <span>DATABASE</span><span> database_name </span><span>[</span><span> ON [ PRIMARY </span><span>]</span> <span>filespec<span>></span> <span>[</span><span> ,...n </span><span>]</span> <span>[</span><span> , <filegroup> [ ,...n </filegroup></span><span>]</span><span> ] </span><span>[</span><span> LOG ON <filespec> [ ,...n </filespec></span><span>]</span><span> ] ] </span><span>[</span><span> COLLATE collation_name </span><span>]</span> <span>filespec<span>></span> ::<span>=</span><span> { ( NAME </span><span>=</span><span> logical_file_name , FILENAME </span><span>=</span> { <span>'</span><span>os_file_name</span><span>'</span> <span>|</span> <span>'</span><span>filestream_path</span><span>'</span><span> } </span><span>[</span><span> , SIZE = size [ KB | MB | GB | TB </span><span>]</span><span> ] </span><span>[</span><span> , MAXSIZE = { max_size [ KB | MB | GB | TB </span><span>]</span> <span>|</span><span> UNLIMITED } ] </span><span>[</span><span> , FILEGROWTH = growth_increment [ KB | MB | GB | TB | % </span><span>]</span><span> ] ) }</span></span></span>
ON:用来定义数据库的数据文件。PRIMARY指出其后所定义的文件是主数据文件,如果省略,则第一个定义的文件是主数据文件。
LOG ON:用来定义数据库的日志文件。如果没有LOG ON,SQL Server将自动创建一个日志文件。
数据库中的文件类型与推荐扩展名:主要数据文件.mdf ,次要数据文件.ndf ,事务日志.ldf 。
创建未指定文件的数据库:
<span>--</span><span> Drop the database if it already exists</span> <span>IF</span> <span>EXISTS</span><span> ( </span><span>SELECT</span><span> name </span><span>FROM</span><span> sys.databases </span><span>WHERE</span> name <span>=</span> N<span>'</span><span>Portal</span><span>'</span><span> ) </span><span>DROP</span> <span>DATABASE</span><span> Portal </span><span>GO</span> <span>CREATE</span> <span>DATABASE</span><span> Portal </span><span>GO</span>
创建指定数据文件和事务日志文件的数据库:
<span>CREATE</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ON</span> <span>PRIMARY</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal.mdf</span><span>'</span><span> , SIZE </span><span>=</span><span> 5MB , FILEGROWTH </span><span>=</span><span> 1MB ) </span><span>LOG</span> <span>ON</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal_log</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_log.ldf</span><span>'</span><span> , SIZE </span><span>=</span><span> 2MB , FILEGROWTH </span><span>=</span> <span>10</span><span>%</span><span> )</span>
创建数据库指定多个数据及事务日志文件:
<span>CREATE</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ON</span> <span>PRIMARY</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal.mdf</span><span>'</span><span> , SIZE </span><span>=</span><span> 5MB , FILEGROWTH </span><span>=</span><span> 1MB ), ( NAME </span><span>=</span> N<span>'</span><span>Portal_Data_2014</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_Data_2014.ndf</span><span>'</span><span> , SIZE </span><span>=</span><span> 5MB , FILEGROWTH </span><span>=</span><span> 1MB ) </span><span>LOG</span> <span>ON</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal_log</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_log.ldf</span><span>'</span><span> , SIZE </span><span>=</span><span> 2MB , FILEGROWTH </span><span>=</span> <span>10</span><span>%</span><span> ), ( NAME </span><span>=</span> N<span>'</span><span>Portal_log_2014</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_log_2014.ldf</span><span>'</span><span> , SIZE </span><span>=</span><span> 2MB , FILEGROWTH </span><span>=</span> <span>10</span><span>%</span><span> )</span>
创建具有文件组的数据库:
<span>CREATE</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ON</span> <span>PRIMARY</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal.mdf</span><span>'</span><span> , SIZE </span><span>=</span><span> 10MB , FILEGROWTH </span><span>=</span><span> 1MB ), FILEGROUP </span><span>[</span><span>div2014</span><span>]</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal_Data_2014</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_Data_2014.ndf</span><span>'</span><span> , SIZE </span><span>=</span><span> 5MB , FILEGROWTH </span><span>=</span><span> 1MB ) </span><span>LOG</span> <span>ON</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal_log</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_log.ldf</span><span>'</span><span> , SIZE </span><span>=</span><span> 2MB , FILEGROWTH </span><span>=</span> <span>10</span><span>%</span><span> )</span>
2. 修改数据库
修改数据库语法:
<span>ALTER</span> <span>DATABASE</span><span> database_name { </span><span>add_or_modify_files<span>></span> <span>|</span> <span>add_or_modify_filegroups<span>></span><span> } </span><span>[</span><span>;</span><span>]</span> <span>add_or_modify_files<span>></span>::<span>=</span><span> { </span><span>ADD</span> <span>FILE</span> <span>filespec<span>></span> <span>[</span><span> ,...n </span><span>]</span> <span>[</span><span> TO FILEGROUP { filegroup_name } </span><span>]</span> <span>|</span> <span>ADD</span> <span>LOG</span> <span>FILE</span> <span>filespec<span>></span> <span>[</span><span> ,...n </span><span>]</span> <span>|</span> REMOVE <span>FILE</span><span> logical_file_name </span><span>|</span> MODIFY <span>FILE</span> <span>filespec<span>></span><span> } </span><span>filespec<span>></span>::<span>=</span><span> ( NAME </span><span>=</span><span> logical_file_name </span><span>[</span><span> , NEWNAME = new_logical_name </span><span>]</span> <span>[</span><span> , FILENAME = {'os_file_name' | 'filestream_path' | 'memory_optimized_data_path' } </span><span>]</span> <span>[</span><span> , SIZE = size [ KB | MB | GB | TB </span><span>]</span><span> ] </span><span>[</span><span> , MAXSIZE = { max_size [ KB | MB | GB | TB </span><span>]</span> <span>|</span><span> UNLIMITED } ] </span><span>[</span><span> , FILEGROWTH = growth_increment [ KB | MB | GB | TB| % </span><span>]</span><span> ] </span><span>[</span><span> , OFFLINE </span><span>]</span><span> ) </span><span>add_or_modify_filegroups<span>></span>::<span>=</span><span> { </span><span>|</span> <span>ADD</span> FILEGROUP <span>filegroup_name</span> <span>[</span><span> CONTAINS FILESTREAM | CONTAINS MEMORY_OPTIMIZED_DATA </span><span>]</span> <span>|</span> REMOVE FILEGROUP <span>filegroup_name</span> <span>|</span> MODIFY FILEGROUP <span>filegroup_name</span><span> { </span><span>filegroup_updatability_option<span>></span> <span>|</span> <span>DEFAULT</span> <span>|</span> NAME <span>=</span><span> new_filegroup_name } } </span><span>filegroup_updatability_option<span>></span>::<span>=</span><span> { { READONLY </span><span>|</span><span> READWRITE } </span><span>|</span> { READ_ONLY <span>|</span><span> READ_WRITE } }</span></span></span></span></span></span></span></span></span></span></span>
新增文件组:
<span>ALTER</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ADD</span> FILEGROUP <span>[</span><span>div2014</span><span>]</span>
新增文件指定文件组:
<span>ALTER</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ADD</span> <span>FILE</span><span> ( NAME </span><span>=</span> N<span>'</span><span>Portal_Data_2014</span><span>'</span><span>, FILENAME </span><span>=</span> N<span>'</span><span>F:\Database\Portal_Data_2014.ndf</span><span>'</span><span> , SIZE </span><span>=</span><span> 5MB , FILEGROWTH </span><span>=</span><span> 1MB ) </span><span>TO</span> FILEGROUP <span>[</span><span>div2014</span><span>]</span>
删除数据库文件:
<span>ALTER</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> REMOVE <span>FILE</span> Portal_Data_2014
修改数据名称:
<span>ALTER</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> MODIFY NAME <span>=</span> <span>[</span><span>Portal_2014</span><span>]</span>
<span>EXEC</span> sp_renamedb <span>[</span><span>Portal</span><span>]</span>, <span>[</span><span>Portal_2014</span><span>]</span>
修改设置默认文件组:
<span>ALTER</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> MODIFY FILEGROUP <span>[</span><span>PRIMARY</span><span>]</span> <span>DEFAULT</span>
3. 删除数据库
删除数据库语法:
<span>DROP</span> <span>DATABASE</span> { database_name <span>|</span> database_snapshot_name } <span>[</span><span> ,...n </span><span>]</span> <span>[</span><span>;</span><span>]</span>
示例:
<span>DROP</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span>
4. 分离数据库
使用系统存储过程sp_detach_db分离数据库。
sp_detach_db <span>[</span><span> @dbname= </span><span>]</span> <span>'</span><span>database_name</span><span>'</span> <span>[</span><span> , [ @skipchecks= </span><span>]</span> <span>'</span><span>skipchecks</span><span>'</span><span> ] </span><span>[</span><span> , [ @keepfulltextindexfile = </span><span>]</span> <span>'</span><span>KeepFulltextIndexFile</span><span>'</span> ]
<span>EXEC</span> sp_detach_db <span>[</span><span>Portal</span><span>]</span>
直接运行分离数据库的SQL语句,可能会提示有进程(用户)正在使用,分离失败。要解决这个问题,先查看哪些进程(用户)正在使用该数据库。
查看用户和进程:
<span>USE</span> <span>[</span><span>master</span><span>]</span><span> sp_who</span>
先结束占用数据库的进程,再分离数据库:
USE [master] KILL 55 KILL 56 KILL 57 <span>EXEC</span> sp_detach_db <span>[</span><span>Portal</span><span>]</span>
5. 附加数据库
使用CREATE DATABASE附加数据库:
<span>CREATE</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ON</span><span> ( FILENAME </span><span>=</span> <span>'</span><span>F:\Database\Portal.mdf</span><span>'</span><span> ) </span><span>FOR</span> ATTACH
<span>CREATE</span> <span>DATABASE</span> <span>[</span><span>Portal</span><span>]</span> <span>ON</span><span> ( FILENAME </span><span>=</span> <span>'</span><span>F:\Database\Portal.mdf</span><span>'</span><span> ), ( FILENAME </span><span>=</span> <span>'</span><span>F:\Database\Portal_log.ldf</span><span>'</span><span> ) </span><span>FOR</span> ATTACH
使用系统存储过程附加数据库:
<span>EXEC</span> sp_attach_db <span>[</span><span>Portal</span><span>]</span>, <span>'</span><span>F:\Database\Portal.mdf</span><span>'</span>
<span>EXEC</span> sp_attach_db <span>[</span><span>Portal</span><span>]</span>, <span>'</span><span>F:\Database\Portal.mdf</span><span>'</span>, 'F:\Database\Portal_log.ldf'
6. 查看数据库信息
SQL Server中可以使用多种方式查看数据库信息,例如使用目录视图、函数、存储过程等。
6.1> 使用目录视图
使用目录视图查看数据库基本信息:
◊ sys.databse_files:查看数据库文件信息;
◊ sys.filegroups:查看数据库组信息;
◊ sys.master_files:查看数据库文件的基本信息和状态信息;
◊ sys.database:数据库和文件目录视图查看数据库的基本信息。
<span>SELECT</span> <span>*</span> <span>FROM</span> sys.databases <span>WHERE</span> name <span>=</span> <span>'</span><span>Northwind</span><span>'</span>

mysqloffersvariousStorageengines,每个suitedfordferentusecases:1)InnodBisidealForapplicationsNeedingingAcidComplianCeanDhighConcurncurnency,supportingtransactionsancions and foreignkeys.2)myisamisbestforread-Heavy-Heavywyworks,lackingtransactionsactionsacupport.3)记忆

MySQL中常见的安全漏洞包括SQL注入、弱密码、权限配置不当和未更新的软件。1.SQL注入可以通过使用预处理语句防止。2.弱密码可以通过强制使用强密码策略避免。3.权限配置不当可以通过定期审查和调整用户权限解决。4.未更新的软件可以通过定期检查和更新MySQL版本来修补。

在MySQL中识别慢查询可以通过启用慢查询日志并设置阈值来实现。1.启用慢查询日志并设置阈值。2.查看和分析慢查询日志文件,使用工具如mysqldumpslow或pt-query-digest进行深入分析。3.优化慢查询可以通过索引优化、查询重写和避免使用SELECT*来实现。

要监控MySQL服务器的健康和性能,应关注系统健康、性能指标和查询执行。1)监控系统健康:使用top、htop或SHOWGLOBALSTATUS命令查看CPU、内存、磁盘I/O和网络活动。2)追踪性能指标:监控查询每秒数、平均查询时间和缓存命中率等关键指标。3)确保查询执行优化:启用慢查询日志,记录并优化执行时间超过设定阈值的查询。

MySQL和MariaDB的主要区别在于性能、功能和许可证:1.MySQL由Oracle开发,MariaDB是其分支。2.MariaDB在高负载环境中性能可能更好。3.MariaDB提供了更多的存储引擎和功能。4.MySQL采用双重许可证,MariaDB完全开源。选择时应考虑现有基础设施、性能需求、功能需求和许可证成本。

MySQL使用的是GPL许可证。1)GPL许可证允许自由使用、修改和分发MySQL,但修改后的分发需遵循GPL。2)商业许可证可避免公开修改,适合需要保密的商业应用。

选择InnoDB而不是MyISAM的情况包括:1)需要事务支持,2)高并发环境,3)需要高数据一致性;反之,选择MyISAM的情况包括:1)主要是读操作,2)不需要事务支持。InnoDB适合需要高数据一致性和事务处理的应用,如电商平台,而MyISAM适合读密集型且无需事务的应用,如博客系统。

在MySQL中,外键的作用是建立表与表之间的关系,确保数据的一致性和完整性。外键通过引用完整性检查和级联操作维护数据的有效性,使用时需注意性能优化和避免常见错误。


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