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Unique fields that allow nulls in Django
...trings are equal to empty strings for uniqueness checks, under both Django and database rules.
You can force the admin interface to store NULL for an empty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms....
Java using enum with switch statement
...about this:
Use a list of static final ints rather than a type-safe enum and switch on the int value you receive (this is the pre-Java 5 approach)
Switch on either a specified id value (as described by heneryville) or the ordinal value of the enum values; i.e. guideView.GUIDE_VIEW_SEVEN_DAY.ordina...
Truncating long strings with CSS: feasible yet?
Is there any good way of truncating text with plain HTML and CSS, so that dynamic content can fit in a fixed-width-and-height layout?
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Difference in months between two dates
...ssuming the day of the month is irrelevant (i.e. the diff between 2011.1.1 and 2010.12.31 is 1), with date1 > date2 giving a positive value and date2 > date1 a negative value
((date1.Year - date2.Year) * 12) + date1.Month - date2.Month
Or, assuming you want an approximate number of 'average...
Do Facebook Oauth 2.0 Access Tokens Expire?
I am playing around with the Oauth 2.0 authorization in Facebook and was wondering if the access tokens Facebook passes out ever expire. If so, is there a way to request a long-life access token?
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Android - Pulling SQlite database android device
I've looked everywhere and i can't find a real precise answer or a tutorial on how, if it is possible, to do this.
19 Answe...
Cannot set content-type to 'application/json' in jQuery.ajax
...ould seem that the default form-urlencoded content type is considered safe and so does not undergo the extra cross domain checks.
It looks like you will need to add the previously mentioned headers to your servers response to the OPTIONS request. You should of course configure them to allow request...
How to set size for local image using knitr for markdown?
...ge that I would like to include in an .Rmd file which I will then knit and convert to HTML slides with Pandoc . Per this post , this will insert the local image :
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Do I need to heartbeat to keep a TCP connection open?
...s that that communicate via TCP/IP. Component A acts as a server/listener and Component B is the client. The two should communicate as quickly as possible. There can only ever be one connection at any time (though that is aside to this question). A senior developer at my company has said I need ...
What is a database transaction?
... To do that you have first to withdraw the amount from the source account, and then deposit it to the destination account. The operation has to succeed in full. If you stop halfway, the money will be lost, and that is Very Bad.
In modern databases transactions also do some other things - like ensur...