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updating table rows in postgres using subquery
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Postgres allows:
UPDATE dummy
SET customer=subquery.customer,
address=subquery.address,
partn=subquery.partn
FROM (SELECT address_id, customer, address, partn
FROM /* big hairy SQL */ ...) AS subquery
WHERE dummy.address_id=subquery.address_id;
Th...
Posting a File and Associated Data to a RESTful WebService preferably as JSON
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I asked a similar question here:
How do I upload a file with metadata using a REST web service?
You basically have three choices:
Base64 encode the file, at the expense of increasing the data size by around 33%, and add processing overhead in both the server and the client for encod...
iPhone App Icons - Exact Radius?
...is greater then it will show black around the edges/corners.
Edit: See comment from @devin-g-rhode and you can see that any future icon sizes should have a 1:6.4 ratio of corner radius to icon size. There is also a very good answer from https://stackoverflow.com/a/29550364/396005 which has the loc...
Why was “Avoid Enums Where You Only Need Ints” removed from Android's performance tips?
...ums Where You Only Need Ints" was removed from the official developer documentation . (See Why doesn't Android use more enums? for the old section content)
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Difference between numpy.array shape (R, 1) and (R,)
In numpy , some of the operations return in shape (R, 1) but some return (R,) . This will make matrix multiplication more tedious since explicit reshape is required. For example, given a matrix M , if we want to do numpy.dot(M[:,0], numpy.ones((1, R))) where R is the number of rows (of co...
What is the difference between CMD and ENTRYPOINT in a Dockerfile?
In Dockerfiles there are two commands that look similar to me: CMD and ENTRYPOINT . But I guess that there is a (subtle?) difference between them - otherwise it would not make any sense to have two commands for the very same thing.
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What are the differences between django-tastypie and djangorestframework? [closed]
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As the author of django-rest-framework, I've got an obvious bias ;) but my hopefully-fairly-objective opinion on this is something like:
TastyPie
As Torsten noted, you're not going to go far wrong with something written by the same peeps as the awesome d...
Does Python support multithreading? Can it speed up execution time?
... the GIL does is make sure only one thread is executing Python code at a time; control still switches between threads.
What the GIL prevents then, is making use of more than one CPU core or separate CPUs to run threads in parallel.
This only applies to Python code. C extensions can and do release ...
nodeValue vs innerHTML and textContent. How to choose?
I'm using plain js to alter the inner text of a label element, and I wasn't sure on what grounds I should use innerHTML or nodeValue or textContent. I don't need to create a new node or change the HTML elements or anything — just replace the text. Here's an example of the code:
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XPath to select multiple tags
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/a/b/*[self::c or self::d or self::e]
Do note that this
a/b/*[local-name()='c' or local-name()='d' or local-name()='e']
is both too-long and incorrect. This XPath expression will select nodes like:
OhMy:c
NotWanted:d
QuiteDifferent:e
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