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Rails :dependent => :destroy VS :dependent => :delete_all
...s with the callback.
The :delete_all is made directly in your application and deletes by SQL :
DELETE * FROM users where compagny_id = XXXX
With the :destroy, there is an instantiation of all of your children. So, if you can't destroy it or if each has their own :dependent, its callbacks can be ...
What is the difference between Lisp-1 and Lisp-2?
I have tried to understand the difference between Lisp-1 and Lisp-2 and how this relates to Clojure but I still do not understand properly. Can anyone enlighten me?
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How to configure PostgreSQL to accept all incoming connections
...of IPs to be authorized, you could edit /var/lib/pgsql/{VERSION}/data file and put something like
host all all 172.0.0.0/8 trust
It will accept incoming connections from any host of the above range.
Source: http://www.linuxtopia.org/online_books/database_guides/P...
Name of this month (Date.today.month as name)
I'm using Date.today.month to display the month number. Is there a command to get the month name, or do I need to make a case to get it?
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How to change owner of PostgreSql database?
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Note, all tables and sequences inside the database will still be assigned to the original owner.
– Cerin
Nov 2 '16 at 0:52
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Get the value of an instance variable given its name
...variable_get("@#{name}")
There is no need to use + or intern; Ruby will handle this just fine. However, if you find yourself reaching into another object and pulling out its ivar, there's a reasonably good chance that you have broken encapsulation.
If you explicitly want to access an ivar, the ri...
Force point (“.”) as decimal separator in java
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Yeah, but you don't need to choose between US and UK. ????
– speedogoo
Jun 17 '16 at 8:43
2
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Delete sql rows where IDs do not have a match from another table
... @Pacerier - "wrong" is a bit strong. To make sure people understand, the answers do work if fileidis non-nullable. Also, the third solution (NOT IN) only requires that f.id by non-nullable. Presumably that is a primary key, so it would be.
– ToolmakerSteve
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How do I merge a git tag onto a branch
... the other way? Merge a branch to the tag? I tried "git checkout tag_name" and "git merge branch". But ended up checking out the branch instead of merging.
– learner
Jan 20 at 12:52
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What is the PostgreSQL equivalent for ISNULL()
...ited Jan 14 '12 at 2:28
Erwin Brandstetter
439k9696 gold badges809809 silver badges969969 bronze badges
answered Feb 6 '10 at 20:02
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