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SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
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Without the update-and-join notation (not all DBMS support that), use:
UPDATE QuestionTrackings
SET QuestionID = (SELECT QuestionID
FROM AnswerTrackings
WHERE AnswerTrackings.AnswerID = QuestionTrackings.AnswerID)
...
Django. Override save for model
...self._image_changed = True
# Or put whole logic in here
small = rescale_image(self.image,width=100,height=100)
self.image_small=SimpleUploadedFile(name,small_pic)
def get_image(self):
return self._image
image = property(get_image, set_image)
# this is ...
How to print out the method name and line number and conditionally disable NSLog?
...lot:
#ifdef DEBUG
# define DLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)
#else
# define DLog(...)
#endif
// ALog always displays output regardless of the DEBUG setting
#define ALog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE_...
Insert, on duplicate update in PostgreSQL?
...it would be much slower, because each upsert would be its' own individual call into the database.
– baash05
Mar 1 '12 at 0:27
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Cross field validation with Hibernate Validator (JSR 303)
... fields; cross-field validation should be done at the class level. Additionally, the JSR-303 Section 2.2 preferred way to express multiple validations of the same type is via a list of annotations. This allows the error message to be specified per match.
For example, validating a common form:
@F...
How to generate a random number in C++?
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The most fundamental problem of your test application is that you call srand once and then call rand one time and exit.
The whole point of srand function is to initialize the sequence of pseudo-random numbers with a random seed.
It means that if you pass the same value to srand in two differ...
Java Keytool error after importing certificate , “keytool error: java.io.FileNotFoundException & Acc
...mmand prompt in administrator mode. If not, you can also go to start -> all programs -> accessories -> right click command prompt and click 'run as administrator'.
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How to manually expand a special variable (ex: ~ tilde) in bash
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Using eval is a horrible suggestion, it's really bad that it gets so many upvotes. You will run into all sorts of problems when the variable's value contains shell meta characters.
– user2719058
Aug 31 '14 at 19:47
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Lazy Method for Reading Big File in Python?
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To write a lazy function, just use yield:
def read_in_chunks(file_object, chunk_size=1024):
"""Lazy function (generator) to read a file piece by piece.
Default chunk size: 1k."""
while True:
data = file_object.read(chunk_size)
if not data:
...
How to keep a Python script output window open?
...w.
Add code to wait at the end of your script. For Python2, adding ...
raw_input()
... at the end of the script makes it wait for the Enter key. That method is annoying because you have to modify the script, and have to remember removing it when you're done. Specially annoying when testing other ...