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How do you write a migration to rename an ActiveRecord model and its table in Rails?
... add_index :old_table_name, :column_name
end
end
And rename your files etc, manually as other answers here describe.
See: http://api.rubyonrails.org/classes/ActiveRecord/Migration.html
Make sure you can rollback and roll forward after you write this migration. It can get tricky if you get some...
How can I list ALL grants a user received?
...rants (e.g., grants via roles, system privileges such as select any table, etc.), here are some additional queries:
System privileges for a user:
SELECT PRIVILEGE
FROM sys.dba_sys_privs
WHERE grantee = <theUser>
UNION
SELECT PRIVILEGE
FROM dba_role_privs rp JOIN role_sys_privs rsp ON (...
MySQL vs MongoDB 1000 reads
... to perform:
One index lookup on the collection (assuming the entity is fetched by id)
Retrieve the contents of one database page (the actual binary json document)
So a b-tree lookup, and a binary page read. Log(n) + 1 IOs. If the indexes can reside entirely in memory, then 1 IO.
In MySQL with ...
How to access outer class from an inner class?
...ass_2": subclass_2}
The main code, "production ready" (without comments, etc.). Remember to replace all of each value in angle brackets (e.g. <x>) with the desired value.
class <higher_level_class>:
def __init__(self):
subclasses = self._subclass_container()
self....
Generating a drop down list of timezones with PHP
...' => 'Europe/London',
'(GMT+00:00) Greenwich Mean Time : Dublin' => 'Etc/Greenwich',
'(GMT+00:00) Lisbon' => 'Europe/Lisbon',
'(GMT+00:00) London' => 'Europe/London',
'(GMT+00:00) Monrovia' => 'Africa/Monrovia',
'(GMT+00:00) UTC' => 'UTC',
'(GMT+01:00) Amsterdam' => 'Europe/Amst...
What is an 'endpoint' in Flask?
...r Y reasons (someone refactored the code and found a more appropriate name etc...). The auto-generated endpoints by Flask helps you handle the changes of url. The explicit endpoint helps you deal with url changes and name changes of your func.
– IMCoins
Feb 20 ...
encryption/decryption with multiple keys
...o that AES-256 session key, and your recipient keys are your RSA/DSA/ECDSA/etc. assymetric key in this case.
One reason for doing it this way is that symmetric cryptographic algorithms like AES are generally a lot faster than asymmetric ones like RSA. GnuPG thus only has to encrypt ~256 bits (the ...
GUI not working after rewriting to MVC
...SING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(color);
g2d.fillOval(x, y, size, size);
}
@Override
public int getIconWidth() {
return size;
}
@Override
public int getIconHeight() {
...
Enabling ProGuard in Eclipse for Android
...to be seen... Despite doing the export multiple times, restarting Eclipse, etc. Any idea why? and how to fix this? Thanks.
– Bill The Ape
Jan 6 '12 at 2:54
...
In absence of preprocessor macros, is there a way to define practical scheme specific flags at proje
...'t want to have to set them and keep them up to date for different targets etc. Also, in our mixed codebase, we didn't want to make remember to set our flags appropriately all the time for each language.
For ours, we declared a file in ObjC
PreProcessorMacros.h
extern BOOL const DEBUG_BUILD;
I...