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How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
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:
...
How to have the cp command create any necessary folders for copying a file to a destination [duplica
... the mkdir/cp command above. It just creates a single level of folder. Actually I'm not sure when it can be useful.
– Penghe Geng
Apr 13 '15 at 14:30
...
Max or Default?
...wiggering the spacklerorke, and riding the flying unicorn to Neverland are all meaningless, impossible, undefined.
Now, what is it that you actually want to do?
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How To Create Table with Identity Column
...TH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)
) ON [PRIMARY]
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Show all Elasticsearch aggregation results/buckets and not just 10
I'm trying to list all buckets on an aggregation, but it seems to be showing only the first 10.
4 Answers
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Backwards migration with Django South
Ok, so this seems like a really silly thing to ask, and I'm sure I'm missing something somewhere.
3 Answers
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Eclipse error: 'Failed to create the Java Virtual Machine'
...swered Sep 4 '11 at 22:52
Matt BallMatt Ball
323k8585 gold badges598598 silver badges672672 bronze badges
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How to unit test an object with database queries
I've heard that unit testing is "totally awesome", "really cool" and "all manner of good things" but 70% or more of my files involve database access (some read and some write) and I'm not sure how to write a unit test for these files.
...
Assignment in an if statement
... = value as T;
if (t != null)
{
action(t);
}
}
Then call it with:
animal.AsIf<Dog>(dog => {
// Use dog in here
});
Alternatively, you could combine the two:
public static void AsIf<T>(this object value, Action<T> action) where T : class
{
// EVI...