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How does Rails keep track of which migrations have run for a database?
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Rails creates a table in your database called schema_migrations to keep track of which migrations have run.
The table contains a single column, version. When Rails runs a migration, it takes the leading digits in the migration's file name and inserts a row for that "version",...
Git: “Not currently on any branch.” Is there an easy way to get back on a branch, while keeping the
... hash of last commit. Checkout the branch you wish to be at, and git merge _hash_
– Daniel
May 31 '12 at 13:31
BE REAL...
What are the differences between struct and class in C++?
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That's not really a second difference, it's just that the question stated the difference incompletely. All subobjects are private by default when using the class, public by default with struct, and both define a class type.
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What is the preferred syntax for defining enums in JavaScript?
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This isn't much of an answer, but I'd say that works just fine, personally
Having said that, since it doesn't matter what the values are (you've used 0, 1, 2), I'd use a meaningful string in case you ever wanted to output the current value.
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How to get memory available or used in C#
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It should probably be noted that a call to GetCurrentProcess will itself allocate quite a lot of resources. Call Dispose on the returned process when done, or wrap the whole code in a "using" scope.
– Mathias Lykkegaard Lorenzen
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Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a con
...able of a class with the mutable keyword. As far as I can see it simply allows you to modify a variable in a const method:
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How do HashTables deal with collisions?
...lookups in hash tables very slow.
Option 2: If the hash table entries are all full then the hash table can increase the number of buckets that it has and then redistribute all the elements in the table. The hash function returns an integer and the hash table has to take the result of the hash funct...
How to get Maven project version to the bash command line
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I'm removing all logging (INFO,WARNING,etc) and 'Download' messages with mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version|grep -Ev '(^\[|Download\w+:)'
– Chadwick
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How to do 3 table JOIN in UPDATE query?
... it had something to do with ON UPDATE CURRENT_TIMESTAMP, I just added manually the update and it fixed it, just saying if it happens to anyone else
– eric.itzhak
Jun 6 '16 at 13:35
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Creating a new user and password with Ansible
... parameter.
There you'll see that your password must be hashed.
- hosts: all
user: root
vars:
# created with:
# python -c 'import crypt; print crypt.crypt("This is my Password", "$1$SomeSalt$")'
password: $1$SomeSalt$UqddPX3r4kH3UL5jq5/ZI.
tasks:
- user: name=tset password={...