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Fastest check if row exists in PostgreSQL
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How about simply:
select 1 from tbl where userid = 123 limit 1;
where 123 is the userid of the batch that you're about to insert.
The above query will return either an empty set or a single row, depending on whether there are records with the given userid.
If this turns o...
How do I run Asynchronous callbacks in Playground
...swered Nov 25 '16 at 10:58
bradd123bradd123
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How does a debugger work?
...f how a debugger works will depend on what you are debugging, and what the OS is. For native debugging on Windows you can find some details on MSDN: Win32 Debugging API.
The user tells the debugger which process to attach to, either by name or by process ID. If it is a name then the debugger will l...
Insert all values of a table into another table in SQL
...dited Feb 26 '14 at 1:12
hichris123
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answered Apr 21 '10 at 9:35
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If statement in aspx page
...erver">
<% If Request.QueryString("id_query_param") = 123 Then 'Add some VB comment here,
'which will not be visible in the rendered source code of the aspx page later %>
<!-- add some html content depending on -->
<!-- the conditi...
Can you Run Xcode in Linux?
Can you run Xcode in Linux? Mac OS X was based on BSD Unix, so is it possible?
13 Answers
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How do I fetch a single model in Backbone?
...ers with the hashbang in your URL like so, http://www.mydomain.com/#clocks/123 , but it should work even if you haven't yet.
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Mac OS X 入门操作常见问题集锦（持续更新） - 更多技术 - 清泛网 - 专注C/...
Mac OS X 入门操作常见问题集锦（持续更新）如何截图：shift + command + 3 截整屏shift + command + 4 截窗口（默认png，并保存到桌面）shift + command + Ctrl + 4 如何截图：
shift + command + 3 截整屏
shift + command + 4 截窗口（默认png，并保存...
Setting environment variables on OS X
What is the proper way to modify environment variables like PATH in OS X?
31 Answers
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How to start a background process in Python?
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Note: This answer is less current than it was when posted in 2009. Using the subprocess module shown in other answers is now recommended in the docs
(Note that the subprocess module provides more powerful facilities for spawning new processes and retrieving their results; ...