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SQL - many-to-many table primary key
This question comes up after reading a comment in this question:
5 Answers
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Stop handler.postDelayed()
...ou can use:
handler.removeCallbacksAndMessages(null);
Docs
public final void removeCallbacksAndMessages (Object token)
Added in API level 1 Remove any pending posts of callbacks and sent
messages whose obj is token. If token is null, all callbacks and
messages will be removed.
Or ...
Fastest way to count exact number of rows in a very large table?
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Simple answer:
Database vendor independent solution = use the standard = COUNT(*)
There are approximate SQL Server solutions but don't use COUNT(*) = out of scope
Notes:
COUNT(1) = COUNT(*) = COUNT(PrimaryKey) just in case
Edit:
SQL Server example (1....
Remove duplicated rows
I have read a CSV file into an R data.frame. Some of the rows have the same element in one of the columns. I would like to remove rows that are duplicates in that column. For example:
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Can I use CASE statement in a JOIN condition?
The following image is a part of Microsoft SQL Server 2008 R2 System Views. From the image we can see that the relationship between sys.partitions and sys.allocation_units depends on the value of sys.allocation_units.type . So to join them together I would write something similar to this:
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add created_at and updated_at fields to mongoose schemas
...y to add created_at and updated_at fields to a mongoose schema, without having to pass them in everytime new MyModel() is called?
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Mysql ibdata 丢失或损坏如何通过frm&ibd 恢复数据 - 爬虫/数据库 - 清...
...frm、ibd存在就可以恢复部分数据。注意：
一、这个是对innodb的数据恢复。myisam不需要这么麻烦，只要数据文件存在直接复制过去就可以。
二、大家的mysql数据库必须是按表存放数据的，默认不是，但是大家生产肯定是按分表设...
JavaScript private methods
To make a JavaScript class with a public method I'd do something like:
30 Answers
30
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How to capture the “virtual keyboard show/hide” event in Android?
...s shown or not. I've searched the API and various blogs but can't seem to find anything useful.
16 Answers
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How do I force Postgres to use a particular index?
How do I force Postgres to use an index when it would otherwise insist on doing a sequential scan?
6 Answers
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