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How to drop columns using Rails migration
...olumn :table_name, :column_name
For instance:
remove_column :users, :hobby
would remove the hobby Column from the users table.
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Using .sort with PyMongo
With PyMongo, when I try to retrieve objects sorted by their 'number' and 'date' fields like this:
1 Answer
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How do I get git to default to ssh and not https for new repositories
...stead of HTTPS when connecting to GitHub/BitBucket, so you'll authenticate by certificate by default, instead of being prompted for a password.
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How to check if std::map contains a key without doing insert?
The only way I have found to check for duplicates is by inserting and checking the std::pair.second for false , but the problem is that this still inserts something if the key is unused, whereas what I want is a map.contains(key); function.
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How to write asynchronous functions for Node.js
...ing IO is better. The best way to understand it is to go watch some videos by ryan dahl.
How do I write asynchronous functions for Node?
Just write normal functions, the only difference is that they are not executed immediately but passed around as callbacks.
How should I implement error e...
Naming convention for Scala constants?
...style, camel case with first letter are upper case. It's laid down clearly by Odersky on Programming in Scala.
The style is also followed by the standard library, and has some support in language semantics: identifiers starting with upper case are treated as constants in pattern matching.
(Section...
Two-way encryption: I need to store passwords that can be retrieved
...n:
Keys
The keys are not directly used. Instead, the key is stretched by a standard PBKDF2 derivation.
The key used for encryption is unique for every encrypted block of text. The supplied key therefore becomes a "master key". This class therefore provides key rotation for cipher and auth keys....
Maven-like dependency management for C++? [closed]
... main project, is there a way to avoid having to build all the subprojects by myself?
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PG::ConnectionBad - could not connect to server: Connection refused
...s postgres didn't delete the PID (process id) file.
The PID file is used by postgres to make sure only one instance of the server is running at a time. So when it goes to start again, it fails because there is already a PID file which tells postgres that another instance of the server was started ...
instantiate a class from a variable in PHP?
...d parameters
PHP >= 5.6
As of PHP 5.6 you can simplify this even more by using Argument Unpacking:
// The "..." is part of the language and indicates an argument array to unpack.
$module = new $className(...$arrayOfConstructorParameters);
Thanks to DisgruntledGoat for pointing that out.
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