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Possible to do a MySQL foreign key to one of two possible tables?
...s (
user_id INT NOT NULL,
place_id INT NOT NULL,
place_type VARCHAR(10) -- either 'states' or 'countries'
-- foreign key is not possible
);
There's no way to model Polymorphic Associations using SQL constraints. A foreign key constraint always references one target table.
Polymorphic Ass...
FileNotFoundException while getting the InputStream object from HttpURLConnection
...alusC
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Purpose of Activator.CreateInstance with example?
...Instance("MyAssembly", ClassName))
and can then do stuff like:
obj.A = 100;
That's its purpose. It also has many other overloads such as providing a Type instead of the class name in a string. Why you would have a problem like that is a different story. Here's some people who needed it:
Creat...
How to delete and replace last line in the terminal using bash?
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echo a carriage return with \r
seq 1 1000000 | while read i; do echo -en "\r$i"; done
from man echo:
-n do not output the trailing newline
-e enable interpretation of backslash escapes
\r carriage return
...
How to use dashes in HTML-5 data-* attributes in ASP.NET MVC
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answered Mar 26 '10 at 1:27
Morten MertnerMorten Mertner
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Check if a temporary table exists and delete if it exists before creating a temporary table
...understanding the problem.
The following works fine for me in SQL Server 2005, with the extra "foo" column appearing in the second select result:
IF OBJECT_ID('tempdb..#Results') IS NOT NULL DROP TABLE #Results
GO
CREATE TABLE #Results ( Company CHAR(3), StepId TINYINT, FieldId TINYINT )
GO
select...
How to check if a string is a valid date
I have a string: "31-02-2010" and want to check whether or not it is a valid date.
What is the best way to do it?
14 Answ...
How to print to console when using Qt
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206
If it is good enough to print to stderr, you can use the following streams originally intended ...
Check if object is a jQuery object
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answered Dec 5 '09 at 19:48
Crescent FreshCrescent Fresh
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getActivity() returns null in Fragment function
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Milad Faridnia
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answered Jun 3 '11 at 9:03
PJLPJL
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