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Windows、Linux开放指定端口 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...口默认是被防火墙拦截禁止外部访问的。本文简要介绍了如何在不关闭防火墙的情况下开放指定端口。Windows篇：
以下步骤中未提供截图的按照默认设置即可：
设置后立即生效。
Linux篇：
vi /etc/sysconfig/iptables
添...
MySQL ON DUPLICATE KEY - last insert id?
...LAST_INSERT_ID(3000)) ON DUPLICATE KEY UPDATE id = LAST_INSERT_ID(id + 1);
SELECT LAST_INSERT_ID();
If the prefix exists, it will increment it and populate last_insert_id.
If the prefix does not exist, it will insert the prefix with the value 3000 and populate last_insert_id with 3000.
...
How to remove constraints from my MySQL table?
...an show the names of the foreign keys by using this query, as shown here:
SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE REFERENCED_TABLE_SCHEMA = '<database>' AND REFERENCED_TABLE_NAME = '<table>';
Then remove the foreign key by running the before mentioned DR...
Using MySQL with Entity Framework [closed]
...link - users can now click right through rather than have to copy/paste or select/goto
– kͩeͣmͮpͥ ͩ
Apr 18 '11 at 13:58
7
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How do I UPDATE from a SELECT in SQL Server?
... SQL Server , it is possible to insert rows into a table with an INSERT.. SELECT statement:
35 Answers
...
What is SQL injection? [duplicate]
...ue for any language), which might be used to handle a user login.
$sql = "SELECT FROM users WHERE username='".$_GET['username']."' AND password='".$_GET['password']."'";
The harm is done when the user enters something like
administrator'; --
... for the username. Without proper encoding the...
How to reset AUTO_INCREMENT in MySQL?
... it will set NULL auto-inc value on information_schema; check SELECT AUTO_INCREMENT FROM information_schema.tables WHERE table_name = 'my_table' AND table_schema = DATABASE( ) ;
– K-Gun
Dec 5 '15 at 0:42
...
Display open transactions in MySQL
... the current transaction list in InnoDB with the query below if you want.
SELECT * FROM information_schema.innodb_trx\G
From the document:
The INNODB_TRX table contains information about every transaction (excluding read-only transactions) currently executing inside InnoDB, including whether t...
How to change the CHARACTER SET (and COLLATION) throughout a database?
...re schema to utf8. Hope this helps!
-- Change DATABASE Default Collation
SELECT DISTINCT concat('ALTER DATABASE `', TABLE_SCHEMA, '` CHARACTER SET utf8 COLLATE utf8_unicode_ci;')
from information_schema.tables
where TABLE_SCHEMA like 'database_name';
-- Change TABLE Collation / Char Set
SELECT...
Dropping Unique constraint from MySQL table
...AINT unq_tab_id UNIQUE(id));
-- checking constraint name if autogenerated
SELECT * FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS WHERE TABLE_NAME = 'tab';
-- dropping constraint
ALTER TABLE tab DROP CONSTRAINT unq_tab_id;
db<>fiddle demo
...