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Understanding :source option of has_one/has_many through of Rails
...'ve chosen to namespace the Dog::Breed, because we want to access Dog.find(123).breeds as a nice and convenient association.
Now, if we now want to create a has_many :dog_breeds, :through => :dogs association on Pet, we suddenly have a problem. Rails won't be able to find a :dog_breeds associati...
How can I start PostgreSQL server on Mac OS X?
...nchctl plists to start automatically. For more information, run brew info postgres.
Start manually
pg_ctl -D /usr/local/var/postgres start
Stop manually
pg_ctl -D /usr/local/var/postgres stop
Start automatically
"To have launchd start postgresql now and restart at login:"
brew services start postgre...
Open multiple Eclipse workspaces on the Mac
... be the officially supported way to do this as of 10.5. Earlier version of OS X and even 10.5 and up should still work using the following instructions though.
Open the command line (Terminal)
Navigate to your Eclipse installation folder, for instance:
cd /Applications/eclipse/
cd /Developer/...
how to create a file name with the current date & time in python?
...
@rwbyrd That is odd, I just tried those exact 3 lines (copy-paste) with Python 3.4.1 and 2.7.6 and it works - though with Python 3 you need to use print(timestr). Did you copy this text from above? Perhaps a typo otherwise?
– Levon
...
Activity transition in Android
... Thanks iandisme. overridePengingTransition is API level 5. Is it not possible to do this for level 3 (Android 1.5)?
– hpique
Aug 2 '10 at 16:11
...
How do I create a unique constraint that also allows nulls?
...et_AllowNull
UNIQUE (TicketID, TicketUnique);
If IssueID 1 has ticket 123, the UNIQUE constraint will be on values (123, NULL). If IssueID 2 has no ticket, it will be on (NULL, 2). Some thought will show that this constraint cannot be duplicated for any row in the table, and still allows multip...
Get users by name property using Firebase
...:
Write to Firebase with a unique, known key:
ref.child('users').child('123').set({ "first_name": "rob", "age": 28 })
Append to lists with an auto-generated key that will automatically sort by time written:
ref.child('users').push({ "first_name": "rob", "age": 28 })
Listen for changes in data ...
CPU Privilege Rings: Why rings 1 and 2 aren't used?
...iminished greatly.
The intent by Intel in having rings 1 and 2 is for the OS to put device drivers at that level, so they are privileged, but somewhat separated from the rest of the kernel code.
Rings 1 and 2 are in a way, "mostly" privileged. They can access supervisor pages, but if they attempt ...
Windows batch files: .bat vs .cmd?
...
From this news group posting by Mark Zbikowski himself:
The differences between .CMD and .BAT as far as CMD.EXE is concerned
are: With extensions enabled, PATH/APPEND/PROMPT/SET/ASSOC in .CMD
files will set ERRORLEVEL regardless of error...
Is JavaScript an untyped language?
...licit compiler interjection, the instruction will error during run-time.
"12345" * 1 === 12345 // string * number => number
Strongly typed means there is a compiler, and it wants you an explicit cast from string to integer.
(int) "12345" * 1 === 12345
In either case, some compiler's featur...