欢迎进入Linux社区论坛,与200万技术人员互动交流 >>进入 经常会对一些实用的功能查了一遍又一遍,最后用的时候还要查。还是自己做个记录,生疏的方法用一个记一个。希望能熟练使用。本文不做vim命令介绍,只做个人的遗忘记录,所用内容仅供参考。 本文置顶
欢迎进入Linux社区论坛,与200万技术人员互动交流 >>进入
经常会对一些实用的功能查了一遍又一遍,最后用的时候还要查。还是自己做个记录,生疏的方法用一个记一个。希望能熟练使用。本文不做vim命令介绍,只做个人的遗忘记录,所用内容仅供参考。
本文置顶,长时间持续更新。
1.替换命令
使用场景:用于批量替换文件中的字符
使用命令:
替换技巧有很多,我常用的一个
:n,m s/a/b/g
意思是把从第n行到第m行查找到的所有a都替换成b
2.取消高亮
使用场景:有时查找一个单词或者替换一个单词后,整个文件中会出现查找匹配高亮,想要取消高亮使用下面这条命令
使用命令:
:nohl
3.格式化代码
使用场景:格式化程序代码
使用命令:
在普通模式(normal)下输入 gg=G 格式化全文
在普通模式(normal)下输入 == 逐行格式化代码
待续……

ACID attributes include atomicity, consistency, isolation and durability, and are the cornerstone of database design. 1. Atomicity ensures that the transaction is either completely successful or completely failed. 2. Consistency ensures that the database remains consistent before and after a transaction. 3. Isolation ensures that transactions do not interfere with each other. 4. Persistence ensures that data is permanently saved after transaction submission.

MySQL is not only a database management system (DBMS) but also closely related to programming languages. 1) As a DBMS, MySQL is used to store, organize and retrieve data, and optimizing indexes can improve query performance. 2) Combining SQL with programming languages, embedded in Python, using ORM tools such as SQLAlchemy can simplify operations. 3) Performance optimization includes indexing, querying, caching, library and table division and transaction management.

MySQL uses SQL commands to manage data. 1. Basic commands include SELECT, INSERT, UPDATE and DELETE. 2. Advanced usage involves JOIN, subquery and aggregate functions. 3. Common errors include syntax, logic and performance issues. 4. Optimization tips include using indexes, avoiding SELECT* and using LIMIT.

MySQL is an efficient relational database management system suitable for storing and managing data. Its advantages include high-performance queries, flexible transaction processing and rich data types. In practical applications, MySQL is often used in e-commerce platforms, social networks and content management systems, but attention should be paid to performance optimization, data security and scalability.

The relationship between SQL and MySQL is the relationship between standard languages and specific implementations. 1.SQL is a standard language used to manage and operate relational databases, allowing data addition, deletion, modification and query. 2.MySQL is a specific database management system that uses SQL as its operating language and provides efficient data storage and management.

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


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