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Is it possible to roll back CREATE TABLE and ALTER TABLE statements in major SQL databases?
...tive.
Is DDL transactional according to this document?
PostgreSQL - yes
MySQL - no; DDL causes an implicit commit
Oracle Database 11g Release 2 and above - by default, no, but an alternative called edition-based redefinition exists
Older versions of Oracle - no; DDL causes an implicit commit
SQL ...
致PHP路上的“年轻人” - PHP - 清泛IT社区，为创新赋能！
...段落的“过来人”，还是想写点东西给“年轻人”。关于如何成长？我直白的答案还是建议通过实践，通过项目来成长。虽然提倡多参加项目，但项目不能是乱七八糟的项目什么都去尝试做，对于刚工作的同学，希望做这两类项...
How is Docker different from a virtual machine?
...e host, see superuser.com/questions/889472/…. However, to illustrate the union filesystem of the containers, there could be a shared layer of libs/bins directly above the docker engine.
– Betamos
Dec 5 '15 at 1:33
...
How to check if field is null or empty in MySQL?
...uld like to check in PHP , then you should do something like :
$query_s =mysql_query("SELECT YOURROWNAME from `YOURTABLENAME` where name = $name");
$ertom=mysql_fetch_array($query_s);
if ('' !== $ertom['YOURROWNAME']) {
//do your action
echo "It was filled";
} else {
echo "it was empty!";
}...
提升大数据分析思想，拥抱大数据未来 - 资讯 - 清泛网 - 专注C/C++及内核技术
...务和世界范围内产生的数据。而所谓公司的麻烦是指，该如何正确利用这些数据——判断出哪些才是相关的、有用的，哪些是需要过滤掉的。最重要的是，哪些才是有助于推动业务发展的。”
因此，思想转变的第一步应是观察...
What does character set and collation mean exactly?
I can read the MySQL documentation and it's pretty clear. But, how does one decide which character set to use? On what data does collation have an effect?
...
How do I modify a MySQL column to allow NULL?
MySQL 5.0.45
6 Answers
6
...
How to get next/previous record in MySQL?
...ding that a primary key colum is not meant as a column to sort by, because MySQL does not guarantee that higher, auto incremented, values are necessarily added at a later time.
If you don't care about this, and simply need the record with a higher (or lower) id then this will suffice. Just don't us...
Can a C# class inherit attributes from its interface?
...e = typeof(T);
return type.GetCustomAttributes(attributeType, true).
Union(type.GetInterfaces().
SelectMany(interfaceType => interfaceType.GetCustomAttributes(attributeType, true))).
Distinct().Cast<T>();
}
...
When to use MongoDB or other document oriented database systems? [closed]
...orm for video- and audio-clips, photos and vector-grafics. We started with MySQL as the database backend and recently included MongoDB for storing all meta-information of the files, because MongoDB better fits the requirements. For example: photos may have Exif information, videos may have audio...