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How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
... are given below, this feature works with multiple conflicting rows and it doesn't require exclusive locking or a retry loop.
The commit adding the feature is here and the discussion around its development is here.
If you're on 9.5 and don't need to be backward-compatible you can stop reading now.
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Does the ternary operator exist in R?
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It doesn't explicitly exist, but you can do:
set.seed(21)
y <- 1:10
z <- rnorm(10)
condition1 <- TRUE
x1 <- if(condition1) y else z
or
condition2 <- sample(c(TRUE,FALSE),10,TRUE)
x2 <- ifelse(condition2, y...
How to create the perfect OOP application [closed]
...ame which is a String
An Item has a Shelf Price which is a Decimal. (Note: does an item really have a price? two identical washing machines might be for sale for different prices at different stores, or at the same store at different times. A better design might be to say that a Pricing Policy relat...
How do I revert all local changes in Git managed project to previous state?
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git reset doesn't reset your changes, git reset --hard does that.
– Cerin
Jul 6 '16 at 16:59
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Is there an “exists” function for jQuery?
... @abhirathore2006 If you use an id selector and the element doesn't exist then length is 0 and doesn't throw exceptions.
– Robert
Jun 29 '17 at 20:35
15
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String comparison in Python: is vs. == [duplicate]
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@Mike: x is x is always True. But that does not imply x == x. NaN is defined as not equal to itself.
– dan04
Jun 7 '10 at 13:12
3
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Why does GCC generate such radically different assembly for nearly the same C code?
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which is pretty much exactly what GCC generates in the assembly.
So why doesn't the compiler optimize fast_trunc_two() to the same thing?
The key part in fast_trunc_one() is the x + (y ^ x) = y optimization. In fast_trunc_two() the x + (y ^ x) expression is being split across the branch.
I suspec...
What is the advantage of using abstract classes instead of traits?
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The second difference doesn't exist in Java8, think.
– Duong Nguyen
Jun 23 '16 at 3:22
14
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Meteor test driven development [closed]
...as well.
Be sure to place your tests in the "tests" folder so that Meteor does not attempt to execute your tests.
Mocha supports CoffeeScript, my choice of scripting language for Meteor projects. Here's a sample Cakefile with tasks for running your Mocha tests. If you are using JS with Meteor, fee...
Convert String to Float in Swift
...ext into your input field (12p.34, or even 12.12.41).
Obviously, if Apple does add a floatValue to Swift this will throw an exception, but it may be nice in the mean time. If they do add it later, then all you need to do to modify your code is remove the extension and everything will work seamlessl...