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Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?
...igure out what's happening. I have a Card entity which contains Sides (usually 2) - and both Cards and Sides have a Stage. I'm using EF Codefirst migrations and the migrations are failing with this error:
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Is there a version control system for database structure changes?
...keeps track of your current db version.
To migrate up, you run a command called "db:migrate" which looks at your version and applies the needed scripts. You can migrate down in a similar way.
The migration scripts themselves are kept in a version control system -- whenever you change the database ...
How to discard local changes in an SVN checkout?
...er changes are not required : """Rest of the changes I made, were for basically debugging, and are no longer required.""" :)
– Cédric Julien
Feb 27 '12 at 10:54
1
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SQL, Postgres OIDs, What are they and why are they useful?
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OIDs basically give you a built-in id for every row, contained in a system column (as opposed to a user-space column). That's handy for tables where you don't have a primary key, have duplicate rows, etc. For example, if you have a t...
How can I search for a commit message on GitHub?
Not in a Git repository , but rather in GitHub specifically - how do I search just the commit messages of a specific repository/branch?
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What does value & 0xff do in Java?
... that notation? x isn't a number or a hex number?
– Callat
Dec 5 '16 at 18:56
3
@KazRodgers - The...
How can I define colors as variables in CSS?
...les, so that I can just change a variable to have the new color applied to all elements that use it?
19 Answers
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Most efficient way to prepend a value to an array
...g-O performance if you are ok with modifying the array in-place. If you really can't mutate the original array then you would do something like the below snippet, which doesn't seem to be appreciably faster than your solution:
a.slice().unshift(0); // Use "slice" to avoid mutating "a".
[Edit 2]
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PostgreSQL - fetch the row which has the Max value for a column
I'm dealing with a Postgres table (called "lives") that contains records with columns for time_stamp, usr_id, transaction_id, and lives_remaining. I need a query that will give me the most recent lives_remaining total for each usr_id
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socket.shutdown vs socket.close
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Here's one explanation:
Once a socket is no longer required,
the calling program can discard the
socket by applying a close subroutine
to the socket descriptor. If a
reliable delivery socket has data
associated with it when a close takes
place, the system continues to attempt
da...