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difference between primary key and unique key
...ey, unique key, etc are collectively called as Candidate Key.
However, DBA selected a key from candidate key for searching records is called Primary key.
Difference between Primary Key and Unique key
1. Behavior: Primary Key is used to identify a row (record) in a table, whereas Unique-key is to...
Paste a multi-line Java String in Eclipse [duplicate]
...iline string, for example:
String name="zzg";
String lines = ""/**~!{
SELECT *
FROM user
WHERE name="$name"
}*/;
System.out.println(lines);
Output：
SELECT *
FROM user
WHERE name="zzg"
sha...
Delete column from pandas DataFrame
...the original
data can be modified without creating a copy.
Popped
Column selection, addition, deletion
Delete column column-name:
df.pop('column-name')
Examples:
df = DataFrame.from_items([('A', [1, 2, 3]), ('B', [4, 5, 6]), ('C', [7,8, 9])], orient='index', columns=['one', 'two', 'three'])
...
Twitter Bootstrap: Text in navbar
...: Is there a standard Bootstrap class that disable the <p> text from selection?
– Matthew Cornell
Dec 11 '15 at 16:31
1
...
How do I remove the “extended attributes” on a file in Mac OS X?
...
Answer (Individual Files)
1. Showcase keys to use in selection.
xattr ~/Desktop/screenshot\ 2019-10-23\ at\ 010212.png
# com.apple.FinderInfo
# com.apple.lastuseddate#PS
# com.apple.metadata:kMDItemIsScreenCapture
# com.apple.metadata:kMDItemScreenCaptureGlobal...
UINavigationController without navigation bar?
...
In Xcode 4.3.2:
Select the navigation controller in the storyboard
Select the Attributes Inspector in the (right) Utilities panel
Under the Navigation Controller category you have two check boxes:
[] Shows Navigation Bar
[] Shows Toolbar
...
How to check if a model has a certain column/attribute?
...
For bonus points use Hash#select: number_hash.select { |key, value| Number.column_names.include? key }
– hgmnz
Nov 10 '09 at 18:31
...
How do I create a simple 'Hello World' module in Magento?
...ck our work). In the admin application
Go to System->Cache Management
Select Refresh from the All Cache menu
Click Save Cache settings
Now, we make sure that Magento knows about the module
Go to System->Configuration
Click Advanced
In the "Disable modules output" setting box, look for yo...
LINQ Orderby Descending Query
...(x=>x.Delivery)
where !t.Items && t.DeliverySelection
orderby t.Delivery.SubmissionDate descending
select t;
share
|
improve t...
Why are Subjects not recommended in .NET Reactive Extensions?
...ach, or for simple cases, you could use something like Observable.Interval.Select(_ => <db fetch>). You may want to use DistinctUntilChanged() to prevent publishing updates when nothing has changed in the source data.
The source of data is some kind of asynchronous api that calls your callb...