大约有 7,000 项符合查询结果（耗时：0.0357秒） [XML]
MongoDB or CouchDB - fit for production? [closed]
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We are running CouchDB as a replacemant for MySQL for our shops (70.0000 items/shop, a total of 4 million attributes of all items, cross connections between items).
Our goals were:
Easy replication from a master-db to several clients with different documents.
Fast p...
How to get ER model of database from server with Workbench
...y to get an ER model of a database from the server that is connected to my MySQL Workbench?
4 Answers
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MySQL, better to insert NULL or empty string?
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Better to Insert NULL for consistency in your database in MySQL. Foreign keys can be stored as NULL but NOT as empty strings.
You will have issues with an empty string in the constraints.
You may have to insert a fake record with a unique empty string to satisfy a Foreign Key cons...
SHFileOperation函数总结（文件夹的移动、复制、删除） - C/C++ - 清泛网 -...
...r.exe保存被重命名的文件,以避免文件名冲突!
上面知道了如何才能使hNameMappings有效
现在如何使用hNameMappings,及其所指的结构大小?并取得这个内存块的内容呢?
hNameMappings 是简单LPVOID无法使用loop
要使用hNameMappings，必须定义一个...
传感器组件 · App Inventor 2 中文网
...步骤是看起来涉及向前运动的步骤。
方法
复位()
重置计步器、距离测量和跑步时间。
保存()
将计步器状态保存至手机。允许累积步数和调用使用计步器的应用程序之间的距离。不同的应用程序将有自己的保存状态。
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MySQL join with where clause
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Post as a guest
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How can I sanitize user input with PHP?
...of that language. For example, if you embed a string in some SQL targeting MySQL, you must escape the string with MySQL's function for this purpose (mysqli_real_escape_string). (Or, in case of databases, using prepared statements are a better approach, when possible.)
Another example is HTML: If yo...
Unknown Column In Where Clause
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See the following MySQL manual page: http://dev.mysql.com/doc/refman/5.0/en/select.html
"A select_expr can be given an alias
using AS alias_name. The alias is used
as the expression's column name and
can be used in GROUP BY, ORDER BY...
SQL Group By with an Order By
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In all versions of MySQL, simply alias the aggregate in the SELECT list, and order by the alias:
SELECT COUNT(id) AS theCount, `Tag` from `images-tags`
GROUP BY `Tag`
ORDER BY theCount DESC
LIMIT 20
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Difference between scaling horizontally and vertically for databases [closed]
...MongoDB, Google Cloud Spanner .. and a good example of vertical scaling is MySQL - Amazon RDS (The cloud version of MySQL). It provides an easy way to scale vertically by switching from small to bigger machines. This process often involves downtime.
In-Memory Data Grids such as GigaSpaces XAP, Coher...