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How can I find which tables reference a given table in Oracle SQL Developer?
...on a table, I can view the constraints, which let me see the foreign keys (and thus which tables are referenced by this table), and I can view the dependencies to see what packages and such reference the table. But I'm not sure how to find which tables reference the table.
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Ways to save enums in database
...store enumerations as numerical ordinal values anymore; it makes debugging and support way too difficult. We store the actual enumeration value converted to string:
public enum Suit { Spade, Heart, Diamond, Club }
Suit theSuit = Suit.Heart;
szQuery = "INSERT INTO Customers (Name, Suit) " +
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Node.js + Nginx - What now?
I've set up Node.js and Nginx on my server. Now I want to use it, but, before I start there are 2 questions:
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Apply a function to every row of a matrix or a data frame
Suppose I have a n by 2 matrix and a function that takes a 2-vector as one of its arguments. I would like to apply the function to each row of the matrix and get a n-vector. How to do this in R?
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pandas: multiple conditions while indexing data frame - unexpected behavior
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As you can see, the AND operator drops every row in which at least one
value equals -1. On the other hand, the OR operator requires both
values to be equal to -1 to drop them.
That's right. Remember that you're writing the condition in te...
How is set() implemented?
...ython source code for set which, according to Achim Domma, is mostly a cut-and-paste from the dict implementation.
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How does a Java HashMap handle different objects with the same hash code?
As per my understanding I think:
14 Answers
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Using a dispatch_once singleton model in Swift
...tl;dr: Use the class constant approach if you are using Swift 1.2 or above and the nested struct approach if you need to support earlier versions.
From my experience with Swift there are three approaches to implement the Singleton pattern that support lazy initialization and thread safety.
Class c...
The written versions of the logical operators
This is the only place I've ever seen and , or and not listed as actual operators in C++. When I wrote up a test program in NetBeans, I got the red underlining as if there was a syntax error and figured the website was wrong, but it is NetBeans which is wrong because it compiled and ran as exp...
What does the “map” method do in Ruby?
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The map method takes an enumerable object and a block, and runs the block for each element, outputting each returned value from the block (the original object is unchanged unless you use map!):
[1, 2, 3].map { |n| n * n } #=> [1, 4, 9]
Array and Range are enume...