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Unable to cast object of type 'System.DBNull' to type 'System.String`
...mber.ToString()
EDIT: Haven't paid attention to ExecuteScalar. It does really return null if the field is absent in the return result. So use instead:
return (accountNumber == null) ? string.Empty : accountNumber.ToString()
...
Import .bak file to a database in SQL server
...e a charm. These are excellent simplified instructions, and they're essentially the same instructions from the official Microsoft link noted in the most voted up answer here.
– Leonardo Lopez
Jun 4 '15 at 15:50
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Fragments onResume from back stack
...ble to the user) after poping out of the backstack, I'd like some kind of callback to be activated within the fragment (to perform certain changes on a shared UI resource, for instance).
...
What is the easiest way to make a C++ program crash?
...I want to make a quick C++ program that crashes on purpose but I don't actually know the best and shortest way to do that, does anyone know what to put between my:
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How can I initialize base class member variables in derived class constructor?
...ince it would destroy encapsulation. Instead, create a constructor in A to allow B (or any subclass of A) to initialize them:
class A
{
protected:
A(int a, int b) : a(a), b(b) {} // Accessible to derived classes
// Change "protected" to "public" to allow others to instantiate A.
private:
...
What is the “continue” keyword and how does it work in Java?
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Generally, I see continue (and break) as a warning that the code might use some refactoring, especially if the while or for loop declaration isn't immediately in sight. The same is true for return in the middle of a method, but fo...
Why is a C++ Vector called a Vector?
The question's pretty self-explanatory really. I know vaguely about vectors in maths, but I don't really see the link to C++ vectors.
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How do I update/upsert a document in Mongoose?
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Mongoose now supports this natively with findOneAndUpdate (calls MongoDB findAndModify).
The upsert = true option creates the object if it doesn't exist. defaults to false.
var query = {'username': req.user.username};
req.newData.username = req.user.username;
MyModel.findOneAndUpd...
Check if an element is present in an array [duplicate]
...
ECMAScript 2016 incorporates an includes() method for arrays that specifically solves the problem, and so is now the preferred method.
[1, 2, 3].includes(2); // true
[1, 2, 3].includes(4); // false
[1, 2, 3].includes(1, 2); // false (second parameter is the index position in this array at...
How to change folder with git bash?
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Go to the directory manually and do right click → Select 'Git bash' option.
Git bash terminal automatically opens with the intended directory. For example, go to your project folder. While in the folder, right click and select the option and 'Git...