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How to add column if not exists on PostgreSQL?
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Here's a short-and-sweet version using the "DO" statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THE...
Tools to selectively Copy HTML+CSS+JS From A Specific Element of DOM [closed]
...he source of websites to see how their markup is built. Tools like Firebug and Chrome Developer Tools make it easy to inspect the code, but if I want to copy a specific section and play around with it locally, it would be a pain to copy all the individual elements and their associated CSS. And proba...
How large should my recv buffer be when calling recv in the socket library
...atagram socket (SOCK_DGRAM) - within TCP/IP, the former corresponds to TCP and the latter to UDP.
How do you know how big to make the buffer passed to recv()?
SOCK_STREAM: It doesn't really matter too much. If your protocol is a transactional / interactive one just pick a size that can hold the ...
When should I use Inline vs. External Javascript?
...l scripts or write them inline with the html code, in terms of performance and ease of maintenance.
18 Answers
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UIRefreshControl without UITableViewController
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On a hunch, and based on DrummerB's inspiration, I tried simply adding a UIRefreshControl instance as a subview to my UITableView. And it magically just works!
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refresh...
window.close and self.close do not close the window in Chrome
...curity feature, introduced a while ago, to stop various malicious exploits and annoyances.
From the latest working spec for window.close():
The close() method on Window objects should, if all the following conditions are met, close the browsing context A:
The corresponding browsing cont...
How can I auto increment the C# assembly version via our CI platform (Hudson)?
Myself and my group are horrendous at incrementing assembly version numbers and we frequently ship assemblies with 1.0.0.0 versions. Obviously, this causes a lot of headaches.
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Has anyone actually implemented a Fibonacci-Heap efficiently?
...g/fibonacci_heap.hpp. This file has apparently been in pending/ for years and by my projections will never be accepted. Also, there have been bugs in that implementation, which were fixed by my acquaintance and all-around cool guy Aaron Windsor. Unfortunately, most of the versions of that file th...
Check if object is file-like in Python
...ts are objects in Python that behave like a real file, e.g. have a read() and a write method(), but have a different implementation. It is and realization of the Duck Typing concept.
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What are the differences among grep, awk & sed? [duplicate]
...ic question, but I am confused about the differences between grep , awk and sed in terms of their role in Unix/Linux system administration and text processing.
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