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How do you write a migration to rename an ActiveRecord model and its table in Rails?
... @mathee: yes, you have to change that manually, or using an IDE that can do Ruby refactoring and commit it to your version control system.
– pupeno
Apr 30 '10 at 9:00
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How to assign the output of a command to a Makefile variable
...tween shell and the opening parentheses and only after removing the space did my makefile output text
– peterchaula
Sep 28 '17 at 15:51
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Does a UNIQUE constraint automatically create an INDEX on the field(s)?
...e keys are in fact B-tree type indexes.
A composite index on (email, user_id) is enough, you don't need a separate index on email only - MySQL can use leftmost parts of a composite index. There may be some border cases where the size of an index can slow down your queries, but you should not worry ...
Explicit vs implicit SQL joins
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Can you provide supporting documentation? This sounds wrong on multiple levels.
– NotMe
May 20 '09 at 14:28
21
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int to hex string
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Try C# string interpolation introduced in C# 6:
var id = 100;
var hexid = $"0x{id:X}";
hexid value:
"0x64"
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“cannot resolve symbol R” in Android Studio
In every instance in all of my classes where I reference R.id.something , the R is in red and it says "cannot resolve symbol R". Also every time there is R.layout.something it is underlined in red and says "cannot resolve method setContentView(?)". The project always builds fine. It is annoyin...
updating table rows in postgres using subquery
... address=subquery.address,
partn=subquery.partn
FROM (SELECT address_id, customer, address, partn
FROM /* big hairy SQL */ ...) AS subquery
WHERE dummy.address_id=subquery.address_id;
This syntax is not standard SQL, but it is much more convenient for this type of query than standard ...
JavaScript private methods
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You can do it, but the downside is that it can't be part of the prototype:
function Restaurant() {
var myPrivateVar;
var private_stuff = function() { // Only visible inside Restaurant()
myPrivateVar = "I can set this here!";
}
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How do I change selected value of select2 dropdown with JqGrid?
... to trigger
$('select').val('1').trigger('change.select2');
See this jsfiddle for examples of these. Thanks to @minlare for Solution 2.
Explanation:
Say I have a best friend select with people's names. So Bob, Bill and John (in this example I assume the Value is the same as the name). First I i...
Convert string to number and add one
I want to turn the value I get from the id into a number and add one to it then pass the new value into the dosomething() function to use. When I tried this and the value is one I get back 11 not 2.
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