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Generate array of all letters and digits
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@Zabba, you just indicated it in your comment ..)
– Nakilon
Jan 31 '11 at 1:56
3
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Postgresql - change the size of a varchar column to lower length
I have a question about the ALTER TABLE command on a really large table (almost 30 millions rows).
One of its columns is a varchar(255) and I would like to resize it to a varchar(40) .
Basically, I would like to change my column by running the following command:
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How do I create a crontab through a script
...diting files manually. I'm planning to create some cron jobs via automated command line, and if editing this file is both the only option, and without significant side effects, I don't see why I shouldn't use it.
– Balmipour
Jan 20 '17 at 11:20
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difference between primary key and unique key
...ultiple columns, e.g. Primary key (CustomerID, ProductID). This is called composite primary key. This is to clarify the first point, as it might be take as it is (read one key => one column ) by new comer to sql : )
– ken
Apr 10 '14 at 13:53
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Can you build dynamic libraries for iOS and load them at runtime?
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Anybody know why that is? To me it just seems completely insane.
– Erik de Castro Lopo
Apr 29 '11 at 3:24
74
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How can the Euclidean distance be calculated with NumPy?
...found here: docs.scipy.org/doc/numpy/reference/generated/… My only real comment was sort of pointing out the connection between a norm (in this case the Frobenius norm/2-norm which is the default for norm function) and a metric (in this case Euclidean distance).
– Mark Lavin...
What is the difference between char * const and const char *?
...ld declare both variables to be int * const; I don't know any way to use a combined declaration to create two variables of that type without a typedef.
– supercat
Apr 12 '13 at 21:57
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How to write a cron that will run a script every day at midnight?
...s--and the *s mean every day of every month.)
Syntax:
mm hh dd mt wd command
mm minute 0-59
hh hour 0-23
dd day of month 1-31
mt month 1-12
wd day of week 0-7 (Sunday = 0 or 7)
command: what you want to run
all numeric values can be replaced by * which means all
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