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@UniqueConstraint annotation in Java
...rite
@Column(unique=true)
String username;
The @UniqueConstraint annotation is for annotating multiple unique keys at the table level, which is why you get an error when applying it to a field.
References (JPA TopLink):
@UniqueConstraint
@Column
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How to dismiss ViewController in Swift?
...s a ViewController in swift by calling dismissViewController in an IBAction
20 Answers
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Creating a zero-filled pandas data frame
...y run into int/float issue if you will be doing something like d.set_value(params) after initializing d to contain 0's. An easy fix is: d = pd.DataFrame(0.0, index=np.arange(len(data)), columns=feature_list).
– ximiki
Aug 29 '17 at 21:03
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What's the difference between QMainWindow, QWidget and QDialog?
... to be shown as a window. It will always appear in a window, and has functions to make it work well with common buttons on dialogs (accept, reject, etc.).
QMainWindow is designed around common needs for a main window to have. It has predefined places for a menu bar, a status bar, a toolbar, and o...
How many parameters are too many? [closed]
Routines can have parameters, that's no news. You can define as many parameters as you may need, but too many of them will make your routine difficult to understand and maintain.
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Force update of an Android app when a new version is available
...ersioning API. The API would look like this:
versionCheck API:
Request parameters:
int appVersion
Response
boolean forceUpgrade
boolean recommendUpgrade
When your app starts, you could call this API that pass in the current app version, and check the response of the versioning API call. ...
Function passed as template argument
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When the function is used in a template parameter it 'decays' into a pointer to the passed function. It's analagous to how arrays decay into pointers when passed as arguments to parameters. Of course, the pointer value is known at compile time and must point to a f...
How do I remove a MySQL database?
You may notice from my last question that a problem caused some more problems, Reading MySQL manuals in MySQL monitor?
6 A...
Mock framework vs MS Fakes frameworks
...owever the approach is different, Fakes generates code to achive this functionality but Mocks framework does not. So is my understanding correct? Is Fakes just another Mock framework
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DateTime2 vs DateTime in SQL Server
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Be careful when adding a .NET DateTime value as a parameter to an SqlCommand, because it likes to assume it's the old datetime type, and you'll get an error if you try to write a DateTime value that's outside that 1753-9999 year range unless you explicitly specify the type a...