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Lost my schema.rb! Can it be regenerated?
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If you run a rake -T it will list all possible rake tasks for your Rails project. One of them is db:schema:dump which will recreate the schema.rb for the Rails app from the database.
bundle exec rake db:schema:dump
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Exploitable PHP functions
...purpose isn't to list functions that should be blacklisted or otherwise disallowed. Rather, I'd like to have a grep -able list of red-flag keywords handy when searching a compromised server for back-doors.
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updating table rows in postgres using subquery
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Postgres allows:
UPDATE dummy
SET customer=subquery.customer,
address=subquery.address,
partn=subquery.partn
FROM (SELECT address_id, customer, address, partn
FROM /* big hairy SQL */ ...) AS subquery
WHERE dummy.addre...
Linq to Entities join vs groupjoin
...groups. This can be turned into a flat list of parent-child pairs by two small additions:
from p in parents
join c in children on p.Id equals c.Id into g // <= into
from c in g.DefaultIfEmpty() // <= flattens the groups
select new { Parent = p.Value, Child = c?.ChildValue }
The ...
Add unique constraint to combination of two columns
...ctive, PersonNumber)
VALUES(N'foo', 1, 22);
GO
Data in the table after all of this:
ID Name Active PersonNumber
---- ------ ------ ------------
1 foo 1 22
2 foo 0 22
Error message on the last insert:
Msg 2627, Level 14, State 1, Line 3
Violation of UNIQUE KEY c...
When serving JavaScript files, is it better to use the application/javascript or application/x-javas
...r js in your pages, IE7 and IE8 will not run your script! Blame Microsoft all you want, but if you want most people to run your pages use text/javascript.
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using lodash .groupBy. how to add your own keys for grouped output?
...t hard to wrap my head around. Can you explain the steps in between, especially the pairing and zipping (and the double zip, since _.object is an alias for _.zipObject).
– Benny Bottema
Jul 31 '15 at 9:17
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Why is arr = [] faster than arr = new Array?
...BER, IDENTIFIER)
new Array: NEW, IDENTIFIER
new Array(): NEW, IDENTIFIER, CALL
new Array(5): NEW, IDENTIFIER, CALL (NUMBER)
new Array(5,4): NEW, IDENTIFIER, CALL (NUMBER, NUMBER)
new Array(5, foo): NEW, IDENTIFIER, CALL (NUMBER, IDENTIFIER)
Hopefully this should provide you a sufficient visualizat...
Python Sets vs Lists
...move the object creation now. The setup phase of the timeit loops is only called once (docs.python.org/2/library/timeit.html#timeit.Timer.timeit).
– Ellis Percival
Sep 30 '14 at 10:09
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Wrap a delegate in an IEqualityComparer
...fying. But I still don't understand your hashing policy of t => 0. If all objects always hash to the same thing (zero), then isn't that even more broken than using obj.GetHashCode, per @Dan Tao's point? Why not always force the caller to provide a good hash function?
– Jo...