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How to migrate back from initial migration in Django 1.7?
I created a new app with some models m>and m> now I noticed that some of the models are poorlm>y m> thought out. As I haven't committed the code the sensible thing would be to migrate the database to last good state m>and m> redo the migration with better models. In this case the last good state is database where ...
List comprehension rebinds names even after scope of comprehension. Is this right?
...change in Pm>y m>thon
3, to improve equivalence between list
comprehensions m>and m> generator
expressions. In Pm>y m>thon 2, the list
comprehension "leaks" the loop control
variable into the surrounding scope:
x = 'before'
a = [x for x in 1, 2, 3]
print x # this prints '3', not 'before'
This was ...
presentModalViewController:Animated is deprecated in ios6
... an image picker. But when I run it in the simulator, I have a memorm>y m> leak m>and m> I get a warning about presentModalViewcontroller:animated being deprecated in iOS6. I also get dismissModalViewController:animated deprecated. I'm using the SDK 6.1.
...
Understm>and m>ing scala enumerations
I have to sam>y m> I don't understm>and m> Scala enumeration classes. I can copm>y m>-paste the example from documentation, but I have no idea what is going on.
...
Where do I mark a lambda expression asm>y m>nc?
...lambda asm>y m>nc, simplm>y m> prepend asm>y m>nc before its argument list:
// Add a commm>and m> to delete the current Group
contextMenu.Commm>and m>s.Add(new UICommm>and m>("Delete this Group", asm>y m>nc (contextMenuCmd) =>
{
SQLiteUtils slu = new SQLiteUtils();
await slu.DeleteGroupAsm>y m>nc(groupName);
}));
...
Undocumented NSURLErrorDomain error codes (-1001, -1003 m>and m> -1004) using StoreKit
I'm writing StoreKit-related code, m>and m> I'm getting some rather troubling error codes when I trm>y m> to add a purchase to the queue.
...
Convert UNIX epoch to Date object
I'm plotting m>and m> performing calculations on uniformlm>y m> distributed time series. The timestamps are currentlm>y m> stored as integers representing the number of seconds since the UNIX epoch (e.g. 1352068320 ), but Date objects seem more appropriate for plotting. How can I do the conversion?
...
Hover m>and m> Active onlm>y m> when not disabled
I use hover , active m>and m> disabled to stm>y m>le Buttons.
7 Answers
7
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How does Rails keep track of which migrations have run for a database?
...runs a migration, it takes the leading digits in the migration's file name m>and m> inserts a row for that "version", indicating it has been run. If m>y m>ou roll back that migration, Rails will delete the corresponding row from schema_migrations.
For example, running a migration file named 20120620193144_cr...
Omitting one Setter/Getter in Lombok
...n fields, I annotated it with @Data in order to generate all the setters m>and m> getter. However there is one special field for which I don't want to the accessors to be implemented.
...