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How to check if object (variable) is defined in R?
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R> exists("somethingUnknown")
[1] FALSE
R> somethingUnknown <- 42
R> exists("somethingUnknown")
[1] TRUE
R>
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SQL Add foreign key to existing column
If I am using the following SQL command in SQL Server 2008 to update a table with a foreign key constraint:
6 Answers
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Postgres unique constraint vs index
...k1 foreign key (con_id) references master(con_id),
constraint detail_fk2 foreign key (ind_id) references master(ind_id)
);
Table "public.detail"
Column | Type | Modifiers
--------+---------+-----------
con_id | integer |
ind_id | integer |
Foreign-key constraints:
"detail_fk1" FOR...
How to add anything in through jquery/javascript?
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nickfnickf
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Center image using text-align center?
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24 Answers
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Git cherry pick vs rebase
...ly forked off the "master" branch, and hence it shares commits C0 through C2 with it — effectively, "experiment" is "master" up to, and including, C2 plus commit C3 on top of it. (This is the simplest possible case; of course, "experiment" could contain several dozens of commits on top of its orig...
What is the difference between `after_create` and `after_save` and when to use which?
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after_create only works once - just after the record is first created.
after_save works every...
“Deprecation warning: moment construction falls back to js Date” when trying to convert RFC2822 date
...o either:
Pass in an ISO formatted version of your date string:
moment('2014-04-23T09:54:51');
Pass in the string you have now, but tell Moment what format the string is in:
moment('Wed, 23 Apr 2014 09:54:51 +0000', 'ddd, DD MMM YYYY HH:mm:ss ZZ');
Convert your string to a JavaScript Date object...
SVN checkout ignore folder
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answered Oct 20 '08 at 11:44
Jon TopperJon Topper
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Can javax.persistence.Query.getResultList() return null?
...ification says nothing about it. But Java Persistence with Hibernate book, 2nd edition, says:
If the query result is empty, a null is returned
Hibernate JPA implementation (Entity Manager) return null when you call query.getResultList() with no result.
UPDATE
As pointed out by some users, it...