下面就是大数据量时提高分页的效率的测试代码,分享给大家。
--提高分页效率:实现分页时只读取显示数据,需要先在数据库创建数据库“TestForPaging” use TestForPaging go --创建表SomeData create table SomeData ( id int primary key, name varchar(30) null, description text ) go --插入数据 insert into SomeData values(1,'num1','第1条') go insert into SomeData values(2,'num2','第2条') go insert into SomeData values(3,'num3','第3条') go insert into SomeData values(4,'num4','第4条') go insert into SomeData values(5,'num5','第5条') go --数据条目总数 select count(*) from SomeData go --给每条记录添加一个数据级别 select name,description,ROW_NUMBER() over(order by id desc)as dataLevel from SomeData go --查看指定的数据级别间的数据条目 select dataLevel,name,description from (select name,description,row_number() over(order by id desc)as dataLevel from SomeData) as datawithleverl where dataLevel between 2 and 4 go --实现查看指定的数据级别间的数据条目的存储过程 create procedure GetDataPaged ( @startRowIndex int, @maximumRows int, @sort varchar ) AS --确保指定sort if len(@sort)=0 set @sort='id' --带参数的查询 select dataLevel,name,description from (select name,description,row_number() over(order by @sort desc)as dataLevel from SomeData) AS datawithleverl WHERE dataLevel > (@startRowIndex*10) AND dataLevel <= (@startRowIndex*10 + @maximumRows) go
以上就是本文的的全部内容,希望对大家的学习有所帮助。

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ToaddanewuserwithcomplexpermissionsinMySQL,followthesesteps:1)CreatetheuserwithCREATEUSER'newuser'@'localhost'IDENTIFIEDBY'password';.2)Grantreadaccesstoalltablesin'mydatabase'withGRANTSELECTONmydatabase.TO'newuser'@'localhost';.3)Grantwriteaccessto'

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The best MySQLVARCHAR column length selection should be based on data analysis, consider future growth, evaluate performance impacts, and character set requirements. 1) Analyze the data to determine typical lengths; 2) Reserve future expansion space; 3) Pay attention to the impact of large lengths on performance; 4) Consider the impact of character sets on storage. Through these steps, the efficiency and scalability of the database can be optimized.


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