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ActiveRecord: List columns in table from console
...console. It will enter the shell of your database, whether it is sqlite or mysql.
Then, you can query the table columns using sql command like:
pragma table_info(your_table);
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SQL Server SELECT INTO @variable?
...not all support TOP 1 as Adrian mentioned. SQL Server / MS Access use TOP, MySQL uses LIMIT, and Oracle uses ROWNUM. See w3schools.com/sql/sql_top.asp for more information.
– Tyler
Jul 7 '17 at 12:08
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COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
... are using as well as the type of table in some cases.
For example, using MySQL, count(*) will be fast under a MyISAM table but slow under an InnoDB. Under InnoDB you should use count(1) or count(pk).
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Difference between reduce and foldLeft/fold in functional programming (particularly Scala and Scala
...s fold
Now this is where it gets a little closer to the FP / mathematical roots, and a little trickier to explain. Reduce is defined formally as part of the MapReduce paradigm, which deals with orderless collections (multisets), Fold is formally defined in terms of recursion (see catamorphism) and...
Dokan虚拟磁盘开发实战 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...lphi的例子代码，只能自己去找了。
刚开始时由于不清楚如何用Dokan来实现一个文件系统，所以需要做一些试验，结果一不小心就蓝屏了！悲剧啊，用XP系统已经好多年没遇到蓝屏了。几次蓝屏之后，终于受不了了，于是在VMWare...
How to use Elasticsearch with MongoDB?
...data from everything what is supporting streams (i.e. MongoDB, PostgreSQL, MySQL, JSON files, etc)
Example for MongoDB to Elasticsearch:
Install packages:
npm install elasticbulk
npm install mongoose
npm install bluebird
Create script i.e. script.js:
const elasticbulk = require('elasticbulk')...
Excluding directories in os.walk
...ited by os.walk:
# exclude = set(['New folder', 'Windows', 'Desktop'])
for root, dirs, files in os.walk(top, topdown=True):
dirs[:] = [d for d in dirs if d not in exclude]
From help(os.walk):
When topdown is true, the caller can modify the dirnames list in-place
(e.g., via del or slice assign...
AttributeError: 'module' object has no attribute 'tests'
... modules by executing imports statements in djano's interactive console.
$root@13faefes8: python manage.py shell
Type "help", "copyright", "credits" or "license" for more information (InteractiveConsole)
>>> from app.model.notification import Notification
Traceback (most recent call last):...
Converting an integer to a string in PHP
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Good point. I threw in some mysql_escape_string functions in there to clean it up.
– Chris Thompson
Jun 23 '09 at 23:33
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Ruby on Rails: how do I sort with two columns using ActiveRecord?
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Assuming you're using MySQL,
Model.all(:order => 'DATE(updated_at), price')
Note the distinction from the other answers. The updated_at column will be a full timestamp, so if you want to sort based on the day it was updated, you need to use ...