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What is cardinality in MySQL?
...s per the Wikipedia article linked to by Kami.
Why it is important to consider is that it affects indexing strategy. There will be little point indexing a low cardinality column with only 2 possible values as the index will not be selective enough to be used.
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Using DISTINCT and COUNT together in a MySQL Query
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use
SELECT COUNT(DISTINCT productId) from table_name WHERE keyword='$keyword'
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Elegant ways to support equivalence (“equality”) in Python classes
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Consider this simple problem:
class Number:
def __init__(self, number):
self.number = number
n1 = Number(1)
n2 = Number(1)
n1 == n2 # False -- oops
So, Python by default uses the object identifiers for comparis...
How to access maven.build.timestamp for resource filtering
...it to something newer, fixed it for me, 3.x ex:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>3.1.0</version>
</plugin>
<properties><timestamp>... workaround is no lon...
IOS: create a UIImage or UIImageView with rounded corners
...iew with rounded corners? Because I want take an UIImage and show it inside an UIImageView , but I don't know how to do it.
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android layout: This tag and its children can be replaced by one and a compound drawable
... Romain Guy's answer, here is an example.
Before:
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:padding="5dp" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
...
NSInvocation for Dummies?
...ting an NSInvocation object to say: "Hey, if you want to undo what I just did, send this message to that object, with these arguments". You give the NSInvocation object to the NSUndoManager, and it adds that object to an array of undoable actions. If the user calls "Undo", NSUndoManager simply looks...
Date only from TextBoxFor()
...n line with this solution, but also have it launch the datepicker like it did with Html.TextboxFor()
– Aaron
Feb 17 '11 at 0:06
50
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Change a Django form field to a hidden field
...alue.
also you may prefer to use in the view:
form.fields['field_name'].widget = forms.HiddenInput()
but I'm not sure it will protect save method on post.
Hope it helps.
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Set cursor position on contentEditable
...e with the standards-based browsers, but will probably fail in IE. I'm providing it as a starting point. IE doesn't support DOM Range.
var editable = document.getElementById('editable'),
selection, range;
// Populates selection and range variables
var captureSelection = function(e) {
// Do...