MySQL

1. Preface ADODB is short for Active Data Objects Data Base. It is a function component used by PHP to access the database. Chen yingguang, the host of the SFS3 System (campus free software exchange network Student Affairs System) plan, decided to

MySQL Performance SettingsAs the website traffic grows, MySQL naturally becomes a bottleneck. Therefore, I have been studying MySQL optimization recently. The first step is to naturally consider MySQL system parameter optimization, as a database

When using mysql, you sometimes need to query records with unique fields. Although mysql provides the keyword distinct to filter out redundant duplicate records, only one record is retained, but it is often used to return the number of records that

Update: it is unnecessary to update a single table. The two are the same, mainly about updating multiple tables.Copy codeThe Code is as follows:Oracle> Oracle has strict requirements for multi-Table update, so sometimes it is not very easy to write.

I found some information, and then I used the two functions concat () and left () in MySQL string processing ()1. CONCAT (str1, str2 ,...)Returns a string from the parameter link. If any parameter is NULL, return NULL. There can be more than two

(See )Assume that a UNION query is required. The first subquery is run as the branch first. If a matched row is found, the query of the second branch is no longer executed. In general, we can write such a UNION query:Copy codeThe Code is as follows:

Copy codeThe Code is as follows:-- QuerySELECT tp. tp_id, tp. tpmc, tp. leveid, tp. tpdz, tp. jgm, tp. scsj, tp. pbzyid, tp. ksbfsj, tp. jsbfsj, tp. status, tp. tpbz FROM qdgl_tupian tp inner join qdgl_pqb pqON tp. tp_id = pq. tpid WHERE pq. bfjgm =

Note three points when uploading EXCEL Data to SQL SERVER!Note: To upload EXCEL Data to SQL SERVER, you must upload the EXCEL Data to the SERVER in advance.Practice: Add a FileUpload upload control in the ASP. NET environment.E. X of the background

After installing the MySQL support library for Python, I encountered a series of problems at one time. Fortunately, Google solved them all. Record it and forget it.1. Download the Python MySQL support libraryAddress:

/* Create a database */Create database tmpGoUSE tmpGo /* Create a database test table */Create table [Scores]([ID] int identity (1, 1)Primary key,[Student] VARCHAR (20 ),[Subject] VARCHAR (30 ),[Score] FLOAT) Go Truncate table Scores/* Insert

Create a trigger. The trigger creation syntax is as follows: Create trigger trigger_name trigger_time trigger_event ON tbl_name for each row trigger_stmt Trigger_name indicates the trigger name, which you can specify; Trigger_time indicates the

In SQL Structured Query Language, LIKE statements play a vital role.The syntax format of the LIKE statement is: select * from table name where field name like corresponding value (substring), which is mainly for struct fields, it is used to retrieve

Some netizens asked me how to automatically back up the MySQL database under win2003. Since it is an automatic backup, I must write a script. I thought, this is not very difficult, it is very easy to implement, backup can be implemented using

(1) The simplest modification method is to modify the character set key value in mysql's my. ini file.,For example, default-character-set = utf8Character_set_server = utf8 After modification, restart the mysql service, service mysql restartUse mysql>

When deploying an experiment system today, the following error is reported:Your 'max _ allowed_packet 'variable is set to less than 16777216 Byte (16 MB ).It is easy to understand, that is, you need to modify the MySQL configuration file, but here

MySQL is a powerful open-source database. With more and more database-driven applications, people have been pushing MySQL to its limit. Here are 101 tips for adjusting and optimizing MySQL installation. Some tips are applicable to specific

Yesterday, I saw a new student in the Group still asking questions about MySQL startup failure. So I summarized several common cases, so I had the right to popularize the post and the old bird flew over.Problem 1: Incorrect directory and file

1. Principle of master-slave synchronization latency in MySQL databases.To talk about the delay principle, we must start with the mysql database master-slave replication principle. mysql master-slave replication is a single-thread operation,The main

1. Difference Between utf8_bin and utf8_general_ci Ci is case insensitive, that is, "case insensitive". a and A are treated as the same in character judgment;Bin is binary, and a and A are treated differently.For example, if you run:SELECT * FROM

Full-database replication is adopted to facilitate the management of mysql 5.5 + rhel5.810.4.11.12 master10.4.11.13 slave--- Master side settings1. To create a replication account, you must have the copy and slave permissions.Mysql> grant