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How to change the foreign key referential action? (behavior)
...re
Example:
I have a UserDetails table refers to Users table:
mysql> SHOW CREATE TABLE UserDetails;
:
:
`User_id` int(11) DEFAULT NULL,
PRIMARY KEY (`Detail_id`),
KEY `FK_User_id` (`User_id`),
CONSTRAINT `FK_User_id` FOREIGN KEY (`User_id`) REFERENCES `Users` (`User_id`)
:
:
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mysql - how many columns is too many?
...tables with many rows, modifying the indexes can take a very long time, as MySQL needs to rebuild all of the indexes in the table. Having the indexes split over several table could make that faster.
Depending on your queries and column types, MySQL could be writing temporary tables (used in more co...
MySQL IF NOT NULL, then display 1, else display 0
... NOT NULL) AS addressexists
This works because TRUE is displayed as 1 in MySQL and FALSE as 0.
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MySQL - length() vs char_length()
...ore accurately UTF-16LE) is what Windows misleadingly calls “Unicode”. MySQL doesn't support UTF-16; instead the usual approach for putting Unicode strings in it is to use UTF-8.
– bobince
Nov 14 '09 at 14:20
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PDO closing connection
Just a rather simple question with regards to PDO compared to MySQLi.
5 Answers
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MQTT与TCP的区别 - 创客硬件开发 - 清泛IT社区，为创新赋能！
... Maori dictionary)。10. mqtt客户端connect时，可以带有用户名和密码，用于验证客户端。服务端可以根据clientid、IP地址、用户名等进行ACL访问控制。可以通过自定义应用消息实现客户端对服务端的身份验证。11. 有商业和开源的mqtt broke...
浅谈TCP优化 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...里就不一一说明了，有兴趣的读者可以自行查阅。
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如何调整「rwnd」到一个合理值
有很多人都遇到过网络传输速度过慢的问题，比如说明明是百兆网络，其最大传输数据的理论值怎么着也得有个十兆，但是实际情况却相距...
MySQL ON DUPLICATE KEY UPDATE for multiple rows insert in single query
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INSERT INTO ... ON DUPLICATE KEY UPDATE will only work for MYSQL, not for SQL Server.
for SQL server, the way to work around this is to first declare a temp table, insert value to that temp table, and then use MERGE
Like this:
declare @Source table
(
name varchar(30),
age decimal(...
MySQL - How to select data by string length
Is there a MySQL function to do this (of course instead of string_length )?
6 Answers
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