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Can table columns with a Foreign Key be NULL?
... INTO child (id, parent_id) VALUES (1, NULL);
-- Query OK, 1 row affected (0.01 sec)
INSERT INTO child (id, parent_id) VALUES (2, 1);
-- ERROR 1452 (23000): Cannot add or update a child row: a foreign key
-- constraint fails (`t/child`, CONSTRAINT `child_ibfk_1` FOREIGN KEY
-- (`parent_id`) REFE...
invalid context 0x0 under iOS 7.0 and system degradation
...core graphics context, but I doubt that's the issue. These invalid context 0x0 error messages are common and easy to reproduce in iOS 7. In fact, I can reproduce the error using storyboard with zero code. I drag a UITextField onto the canvas in IB, run the app, and double tap inside the text field. ...
When should we use mutex and when should we use semaphore
... edited Aug 22 '12 at 7:29
j0k
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answered Aug 22 '12 at 3:12
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How do I center align horizontal menu?
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130
From http://pmob.co.uk/pob/centred-float.htm:
The premise is simple and basically just involves...
Regex to get string between curly braces
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edited Feb 26 at 10:44
answered Jan 5 '09 at 13:25
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How do I do a bulk insert in mySQL using node.js
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edited Apr 27 at 19:04
Agnel Vishal
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answered Jan 10 '13 at 1...
Create a string of variable length, filled with a repeated character
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Working with Enums in android
...u can add values to them like this.
public enum Gender {
MALE("Male", 0),
FEMALE("Female", 1);
private String stringValue;
private int intValue;
private Gender(String toString, int value) {
stringValue = toString;
intValue = value;
}
@Override
publi...
Find if variable is divisible by 2
.../ Will evaluate to true if the variable is divisible by 2
variable % 2 === 0
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Select mySQL based only on month and year
...in my mySQL DB that has some rows. One of this row is a DATE, like this: 2012-02-01
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