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Create unique constraint with null columns
..., menu_id, recipe_id)
WHERE menu_id IS NOT NULL;
CREATE UNIQUE INDEX favo_2col_uni_idx ON favorites (user_id, recipe_id)
WHERE menu_id IS NULL;
This way, there can only be one combination of (user_id, recipe_id) where menu_id IS NULL, effectively implementing the desired constraint.
Possible dra...
Finding duplicates in O(n) time and O(1) space
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edited Nov 25 '15 at 9:44
answered Apr 21 '11 at 3:54
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Adding up BigDecimals using Streams
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3.1. We supply an identity value for addition, namely BigDecimal.ZERO.
3.2. We specify the BinaryOperator<BigDecimal>, which adds two BigDecimal's, via a method reference BigDecimal::add.
Updated answer, after edit
I see that you have added new data, therefore the new answer will become:
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Shadow Effect for a Text in Android? [duplicate]
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207
Perhaps you'd consider using android:shadowColor, android:shadowDx, android:shadowDy, android:...
How to handle initializing and rendering subviews in Backbone.js?
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260
This is a great question. Backbone is great because of the lack of assumptions it makes, but i...
Acronyms in CamelCase [closed]
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206
Some guidelines Microsoft has written about camelCase are:
When using acronyms, use Pascal...
All Ruby tests raising: undefined method `authenticate' for nil:NilClass
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Guillaume
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answered Nov 29 '10 at 22:47
Jeffrey W.Jeffrey ...
Implications of foldr vs. foldl (or foldl')
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The recursion for foldr f x ys where ys = [y1,y2,...,yk] looks like
f y1 (f y2 (... (f yk x) ...))
whereas the recursion for foldl f x ys looks like
f (... (f (f x y1) y2) ...) yk
An important difference here is that if the result of f x y can be computed using only...
Calling clojure from java
...ln (str "(binomial 5 3): " (binomial 5 3)))
(println (str "(binomial 10042 111): " (binomial 10042 111)))
)
If you run it, you should see something like:
(binomial 5 3): 10
(binomial 10042 111): 49068389575068144946633777...
And here's a Java program that calls the -binomial function in the t...
How to print a percentage value in python?
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289
format supports a percentage floating point precision type:
>>> print "{0:.0%}".form...