欢迎进入Windows社区论坛,与300万技术人员互动交流 >>进入 --解决还原数据库目录不对的详细步骤: 1.企业管理器中的方法: --右键"数据库" --所有任务 --还原数据库 --"还原为数据库库"中输入还原后的数据库名 --还原选择"从设备"--选择设备--添加--添加你
欢迎进入Windows社区论坛,与300万技术人员互动交流 >>进入
--解决还原数据库目录不对的详细步骤:
1.企业管理器中的方法:
--右键"数据库"
--所有任务
--还原数据库
--"还原为数据库库"中输入还原后的数据库名
--还原选择"从设备"--选择设备--添加--添加你的备份文件--确定,回到数据库还原的界面
--备份号--选择内容--选择你要恢复那次备份的内容
--选项--将"移至物理文件名"中的物理文件名修改为你的数据文件要存放的文件名
--如果要还原的数据库已经存在,选择"在现有数据库上qz还原"-
-确定
2.用SQL语句的方法(假设你的备份文件名为: c:\xx.bak
--列出备份文件中的逻辑文件名
restore filelistonly from disk='c:\xx.bak'
--用语句恢复,根据上面列出的逻辑文件名使用move选项
restore database 恢复后的数据库名
from disk='c:\xx.bak'
with move '逻辑数据文件名1' to 'c:\物理数据文件名1'
,move '逻辑数据文件名2' to 'c:\物理数据文件名2'
…
,move '逻辑数据文件名n' to 'c:\物理数据文件名n'
没有什么要特别注意的,和企业版之间的备份/还原要注意的东西一样:
1.要注意备份时的设置问题,不要指定多个备份文件,否则还原时也要指定多个备份文件
2.要注意备份的媒体处理方式问题,用重写,而不是追加,否则还原的时候要指定备份号
3.要注意备份的方式,用完全备份,而不是其他备份方式,否则还原时还要其他备份文件支持
[1] [2]

InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB

MySQL/InnoDB supports four transaction isolation levels: ReadUncommitted, ReadCommitted, RepeatableRead and Serializable. 1.ReadUncommitted allows reading of uncommitted data, which may cause dirty reading. 2. ReadCommitted avoids dirty reading, but non-repeatable reading may occur. 3.RepeatableRead is the default level, avoiding dirty reading and non-repeatable reading, but phantom reading may occur. 4. Serializable avoids all concurrency problems but reduces concurrency. Choosing the appropriate isolation level requires balancing data consistency and performance requirements.

MySQL is suitable for web applications and content management systems and is popular for its open source, high performance and ease of use. 1) Compared with PostgreSQL, MySQL performs better in simple queries and high concurrent read operations. 2) Compared with Oracle, MySQL is more popular among small and medium-sized enterprises because of its open source and low cost. 3) Compared with Microsoft SQL Server, MySQL is more suitable for cross-platform applications. 4) Unlike MongoDB, MySQL is more suitable for structured data and transaction processing.

MySQL index cardinality has a significant impact on query performance: 1. High cardinality index can more effectively narrow the data range and improve query efficiency; 2. Low cardinality index may lead to full table scanning and reduce query performance; 3. In joint index, high cardinality sequences should be placed in front to optimize query.

The MySQL learning path includes basic knowledge, core concepts, usage examples, and optimization techniques. 1) Understand basic concepts such as tables, rows, columns, and SQL queries. 2) Learn the definition, working principles and advantages of MySQL. 3) Master basic CRUD operations and advanced usage, such as indexes and stored procedures. 4) Familiar with common error debugging and performance optimization suggestions, such as rational use of indexes and optimization queries. Through these steps, you will have a full grasp of the use and optimization of MySQL.

MySQL's real-world applications include basic database design and complex query optimization. 1) Basic usage: used to store and manage user data, such as inserting, querying, updating and deleting user information. 2) Advanced usage: Handle complex business logic, such as order and inventory management of e-commerce platforms. 3) Performance optimization: Improve performance by rationally using indexes, partition tables and query caches.


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