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When should I use a composite index?
..._C )
will benefit a query that uses those fields for joining, filtering, and sometimes selecting. It will also benefit queries that use left-most subsets of columns in that composite. So the above index will also satisfy queries that need
index( column_A, column_B, column_C )
index( column_A, col...
Query to list number of records in each table in a database
...
If you're using SQL Server 2005 and up, you can also use this:
SELECT
t.NAME AS TableName,
i.name as indexName,
p.[Rows],
sum(a.total_pages) as TotalPages,
sum(a.used_pages) as UsedPages,
sum(a.data_pages) as DataPages,
(sum(...
Turning multi-line string into single comma-separated
... to the hold space and after deleting the introduced newline at the start, convert all newlines to ,'s.
N.B. Could be written:
sed 's/\S\+\s\+//;s/\s.*//;1h;1!H;$!d;x;s/\n/,/g' file
share
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impro...
Checking if an object is a given type in Swift
I have an array that is made up of AnyObject . I want to iterate over it, and find all elements that are array instances.
...
UIPanGestureRecognizer - Only vertical or horizontal
...tyInView:someView];
return fabs(velocity.y) > fabs(velocity.x);
}
And for Swift:
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIPanGestureRecognizer) -> Bool {
let velocity = gestureRecognizer.velocity(in: someView)
return abs(velocity.x) > abs(velocity.y)
}
...
How to create our own Listener interface in android?
...od in MyButton class : void setMyListener(MyListner m1){ this.ml = m1;} and then use this method any time to set your listener object.
– Rakesh Soni
Dec 7 '15 at 10:22
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Releasing memory in Python
...llocator. The int type maintains a freelist with its own allocated memory, and clearing it requires calling PyInt_ClearFreeList(). This can be called indirectly by doing a full gc.collect.
Try it like this, and tell me what you get. Here's the link for psutil.Process.memory_info.
import os
import...
Difference between spring @Controller and @RestController annotation
...
I think @RestController also converts the response to JSON/XML automatically.
– arnabkaycee
Oct 21 '16 at 13:05
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What is the difference between a weak reference and an unowned reference?
...
Both weak and unowned references do not create a strong hold on the referred object (a.k.a. they don't increase the retain count in order to prevent ARC from deallocating the referred object).
But why two keywords? This distinction has...
How to run a PowerShell script without displaying a window?
...he window called PsRun.exe that does exactly that. You can download source and exe file Run scheduled tasks with WinForm GUI in PowerShell. I use it for scheduled tasks.
Edited: as Marco noted this -windowstyle parameter is available only for V2.
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