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“Insert if not exists” statement in SQLite
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If you have a table called memos that has two columns id and text you should be able to do like this:
INSERT INTO memos(id,text)
SELECT 5, 'text to insert'
WHERE NOT EXISTS(SELECT 1 FROM memos WHERE id = 5 AND text = 'text to insert');
If a record...
dplyr: “Error in n(): function should not be called directly”
...produce one of the examples in the dplyr package but am getting this error message. I am expecting to see a new column n produced with the frequency of each combination. What am I missing? I triple checked that the package is loaded.
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Negative weights using Dijkstra's Algorithm
..., but not all graphs in general. For example, consider this graph:
Assume the edges are directed from left to right as in your example,
Your algorithm will work as follows:
First, you set d(A) to zero and the other distances to infinity.
You then expand out node A, setting d(B) to 1, d(C) to...
How to use ng-repeat without an html element
I need to use ng-repeat (in AngularJS) to list all of the elements in an array.
8 Answers
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AngularJs “controller as” syntax - clarification?
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There are several things about it.
Some people don't like the $scope syntax (don't ask me why). They say that they could just use this. That was one of the goals.
Making it clear where a property comes from is really useful too.
You can nest controllers and wh...
What is LINQ and what does it do? [closed]
...l Basic). The techniques for forming these queries do not rely on the implementation details of the thing being queried, so that you can write valid queries against many targets (databases, in-memory objects, XML) with practically no consideration of the underlying way in which the query will be exe...
Can I tell the Chrome script debugger to ignore jquery.js?
Is there a way to tell the Chrome debugger (or maybe Firebug?) to not break within certain files? To assume they're not broken, essentially? This seems like something they might build in.
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Difference between JAX-WS, Axis2 and CXF
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The JAX-WS implementation built into the JDK really is just the basic soap stuff. If you need any of the more complex WS-* things like WS-Security, WS-RM, WS-Policy, etc..., you need to use one of the alternatives like CXF or Metro or Axis2...
What is the best way to paginate results in SQL Server
...ting are two different operations. For the sake of this example, let's assume that the query you're dealing with is
SELECT * FROM Orders WHERE OrderDate >= '1980-01-01' ORDER BY OrderDate
In this case, you would determine the total number of results using:
SELECT COUNT(*) FROM Orders WHERE Or...
Why is the asterisk before the variable name, rather than after the type?
Why do most C programmers name variables like this:
12 Answers
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