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Foreign Key to non-primary key
... have to be linked only to a PRIMARY
KEY constraint in another table; it can also be defined to reference
the columns of a UNIQUE constraint in another table.
So in your case if you make AnotherID unique, it will be allowed. If you can't apply a unique constraint you're out of luck, but this r...
Should I use a data.frame or a matrix?
...ained already in your question: You use data frames if columns (variables) can be expected to be of different types (numeric/character/logical etc.). Matrices are for data of the same type.
Consequently, the choice matrix/data.frame is only problematic if you have data of the same type.
The answe...
Why can't yield return appear inside a try block with a catch?
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I suspect this is a matter of practicality rather than feasibility. I suspect there are very, very few times where this restriction is actually an issue that can't be worked around - but the added complexity in the compiler would be very significant.
There are...
My attempt at value initialization is interpreted as a function declaration, and why doesn't A a(())
... has taught me is what is known as the "most vexing parse", which is classically demonstrated with a line such as
5 Answers...
How is Perl's @INC constructed? (aka What are all the ways of affecting where Perl modules are searc
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We will look at how the contents of this array are constructed and can be manipulated to affect where the Perl interpreter will find the module files.
Default @INC
Perl interpreter is compiled with a specific @INC default value. To find out this value, run env -i perl -V command (env -i i...
When should I use jQuery deferred's “then” method and when should I use the “pipe” method?
jQuery's Deferred has two functions which can be used to implement asynchronous chaining of functions:
3 Answers
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Updating packages in Emacs
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In order to automatically update the list of packages, only if there is no package list already, use the following:
(when (not package-archive-contents)
(package-refresh-contents))
In order to update all installed packages, type package-l...
Clustered vs Non-Clustered
...ed vs. non-clustered index is that the clustered index determines the physical order of the rows in the database. In other words, applying the clustered index to PersonId means that the rows will be physically sorted by PersonId in the table, allowing an index search on this to go straight to the ro...
Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?
Following on from this question , can someone explain the following in Scala:
4 Answers
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How to add a local repo and treat it as a remote repo
I'm trying to make a local repo act as a remote with the name bak for another local repo on my PC, using the following:
4...