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What is causing ERROR: there is no unique constraint matching given keys for referenced table?
...atching given keys for referenced table, and having stared at it for while now I can't figure out why this error arises in this situation.
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How can I use pointers in Java?
I know Java doesn't have pointers, but I heard that Java programs can be created with pointers and that this can be done by the few who are experts in java. Is it true?
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Fastest way(s) to move the cursor on a terminal command line?
... to implement command line input. And so to say, it is very convenient to know Readline bindings since it is used not only in bash. For example, gdb also uses Readline to process input.
In Readline documentation you can find all navigation related bindings (and more):
http://www.gnu.org/software/ba...
Why is lazy evaluation useful?
...ort (filter (< x) xs) ++ [x] ++ quickSort (filter (>= x) xs)
If we now want to find the minimum of the list, we can define
minimum ls = head (quickSort ls)
Which first sorts the list and then takes the first element of the list. However, because of lazy evaluation, only the head gets comp...
F# development and unit testing?
...ange in the process of writing code. I have been using TDD for years in C# now, and really appreciate to have unit tests to know where I am at.
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How much overhead does SSL impose?
I know there's no single hard-and-fast answer, but is there a generic order-of-magnitude estimate approximation for the encryption overhead of SSL versus unencrypted socket communication? I'm talking only about the comm processing and wire time, not counting application-level processing.
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How to search a specific value in all tables (PostgreSQL)?
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@Henno: yes it requires PG-9.1. Edited now to make that explicit. To use it with older versions, you'll have to adapt it.
– Daniel Vérité
May 11 '14 at 12:27
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What is Full Text Search vs LIKE
...Document sets = {d1, d2, d3, d4, ... dn}
Term sets = {t1, t2, t3, .. tn}
Now term-document matrix (which term member of which document) can be represented as:
t1 -> {d1, d5, d9,.. dn}
t2 -> {d11, d50, d2,.. dn}
t3 -> {d23, d67, d34,.. dn}
:
tn -> {d90, d87, d57,.. dn}
When the req...
How to generate keyboard events in Python?
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i have been using this wonderfully, but now i have a small problem, hopefully you can help me - how can i move the mouse X,Y ?
– Inbar Rose
Dec 9 '12 at 18:00
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What's is the difference between include and extend in use case diagram?
...re sometimes” is a very common misconception which has almost taken over now as the de-facto meaning. Here’s a correct approach (in my view, and checked against Jacobson, Fowler, Larmen and 10 other references).
Relationships are dependencies
The key to Include and extend use case relationshi...