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sqlalchemy unique across multiple columns
... declares those in the table definition, or if using declarative as in the __table_args__:
# version1: table definition
mytable = Table('mytable', meta,
# ...
Column('customer_id', Integer, ForeignKey('customers.customer_id')),
Column('location_code', Unicode(10)),
UniqueConstraint...
When to use symbols instead of strings in Ruby?
...iers. For Ruby < 2.2 only use symbols when they aren't generated dynamically, to avoid memory leaks.
Full answer
The only reason not to use them for identifiers that are generated dynamically is because of memory concerns.
This question is very common because many programming languages don't h...
C dynamically growing array
...ynamic array implementations work by starting off with an array of some (small) default size, then whenever you run out of space when adding a new element, double the size of the array. As you can see in the example below, it's not very difficult at all: (I've omitted safety checks for brevity)
type...
Unable to install Maven on Windows: “JAVA_HOME is set to an invalid directory”
...ollowed the Maven tutorial to the letter but I still can't get Maven installed on Windows.
16 Answers
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How can I save a screenshot directly to a file in Windows? [closed]
...ormat format = ImageFormat.PNG; or ImageFormat format = ImageFormat.JPG; All is here for you
– Patrick Desjardins
Oct 1 '08 at 15:31
4
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Can someone explain the right way to use SBT?
...tarted, and why?
I think the sane point is to build immunity to sbt gradually.
Make sure you understand:
scopes format {<build-uri>}<project-id>/config:key(for task-key)
the 3 flavors of settings (SettingKey, TaskKey, InputKey) - read the section called "Task Keys" in http://www.sc...
How to get the original value of an attribute in Rails
...
Before rails 5.1
Appending _was to your attribute will give you the previous value.
For rails 5.1+
Copied from Lucas Andrade's answer below: https://stackoverflow.com/a/50973808/9359123
Appending _was is deprecated in rails 5.1, now you should ap...
Preserving order with LINQ
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Actually, I think Distinct preserves original (first found) order - so {1,2,1,3,1,3,4,1,5} would be {1,2,3,4,5}
– Marc Gravell♦
Oct 15 '08 at 14:33
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How to print a stack trace in Node.js?
...l which stack does not. The info is in the error object if you want to manually create that line I guess.
– studgeek
Aug 30 '12 at 16:54
132
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Routes with Dash `-` Instead of Underscore `_` in Ruby on Rails
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there has to be a better and faster way to convert all routes that has undersore to hyphens
– carbonr
Mar 31 '13 at 17:59
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