测试的时候比较重要,我们可以知道当前交易影响了哪些表 --用于记录 用户 在当前表上什么时候、做的什么操作:update、insert、delete create table TriggerRecord ( operdt datetime,--触发时间 opertp varchar(10),--操作类型:update、insert、delete ope
测试的时候比较重要,我们可以知道当前交易影响了哪些表
--用于记录用户在当前表上什么时候、做的什么操作:update、insert、delete
create table TriggerRecord
(
operdt datetime, --触发时间
opertp varchar(10), --操作类型:update、insert、delete
opertb varchar(50) --表名
)
--这个表于用保存生成的触发器语句,在过程中循环执行
--因为Sqlserver不允许在一个批次同时执行多条create trigger语句
create table T(sqlTrigger varchar(500))
--循环执行存于表中触发器的存储过程
create proc loopExecTrigger
as
begin
declare @sql varchar(500)
declare cur cursor for select sqlTrigger from T
open cur
fetch cur into @sql
while @@fetch_status=0
begin
execute(@sql)
fetch cur into @sql
end
close cur
deallocate cur
delete T
end
--用于生成插入语句的触发器,并将触发器语句保存到表中
select 'insert into T values(''create trigger T_'+name+' on '+name+' for insert as insert into TriggerRecord values(getdate(),''''insert'''','''''+name+''''');'')' from sysobjects where type='U' and name not in('T','TriggerRecord')
--将以上生成的语句拷贝出来执行
--用于生成更新语句的触发器,并将触发器语句保存到表中
select 'insert into T values(''create trigger T_'+name+'_U on '+name+' for update as insert into TriggerRecord values(getdate(),''''update'''','''''+name+''''');'')' from sysobjects where type='U' and name not in('T','TriggerRecord')
--将以上生成的语句拷贝出来执行
--用于生成删除语句的触发器,并将触发器语句保存到表中
select 'insert into T values(''create trigger T_'+name+'_D on '+name+' for delete as insert into TriggerRecord values(getdate(),''''delete'''','''''+name+''''');'')' from sysobjects where type='U' and name not in('T','TriggerRecord')
--将以上生成的语句拷贝出来执行
--执行通过上面语句生成的语句后,再执行存储生成触发器的存储过程
exec loopExecTrigger
--生成删除全部以T开头的触发器的语句
select 'drop trigger '+name+';' from sysobjects where type='TR' and name like 'T_%'
冯立彬的博客

InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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