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How to delete migration files in Rails 3
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I usually:
Perform a rake db:migrate VERSION=XXX on all environments, to the version before the one I want to delete.
Delete the migration file manually.
If there are pending migrations (i.e., the migration I removed was not the...
Properly removing an Integer from a List
... is equal to Integer(1) will be removed. In both cases, the Java compiler selects the closest matching overload.
Yes, there is potential for confusion (and bugs) here, but it is a fairly uncommon use-case.
When the two List.remove methods were defined in Java 1.2, the overloads were not ambiguous...
Connection pooling options with JDBC: DBCP vs C3P0
...operties.getProperty("testOnBorrow")));
poolDataSource.setValidationQuery("SELECT 0");
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Enable remote connections for SQL Server Express 2012
...ar, so good, and entirely expected. But then:
Right-click on TCP/IP and select Properties.
Verify that, under IP2, the IP Address is set to the computer's IP address on the local subnet.
Scroll down to IPAll.
Make sure that TCP Dynamic Ports is blank. (Mine was set to some 5-digit port number.)
...
Handling a Menu Item Click Event - Android
...inflate(R.menu.game_menu, menu);
return true;
}
simple code for menu selected
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.new_game:
newGame();
return true;
case R.id.help:
...
What are CN, OU, DC in an LDAP search?
...N = Common Name
OU = Organizational Unit
DC = Domain Component
These are all parts of the X.500 Directory Specification, which defines nodes in a LDAP directory.
You can also read up on LDAP data Interchange Format (LDIF), which is an alternate format.
You read it from right to left, the right-m...
Why is Scala's immutable Set not covariant in its type?
...ameter of type A due to the contravariance of functions. Set could potentially be contravariant in A, but this too causes issues when you want to do things like this:
def elements: Iterable[A]
In short, the best solution is to keep things invariant, even for the immutable data structure. You'll...
find() with nil when there are no records
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Yes, just do:
Challenge.find_by_id(10)
For Rails 4 and 5:
Challenge.find_by(id: 10)
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CSS Classes & SubClasses
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FYI, when you define a rule like you did above, with two selectors chained together:
.area1.item
{
color:red;
}
It means:
Apply this style to any element that has both the class "area1" and "item".
Such as:
<div class="area1 item">
Sadly it doesn't work in IE6...
How can I check if a var is a string in JavaScript?
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Guys, I really would give an accepted answer to both of you, but I can't, all I can do is +1 to both, than give the accepted answer at who is more near to my specific problem, that I've not fully explained.
– vitt...