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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...
Check if a path represents a file or a folder
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205
Assuming path is your String.
File file = new File(path);
boolean exists = file.exists()...
How to find out client ID of component for ajax update/render? Cannot find component with expression
...e following chapter.
Note: if it happens to contain iteration index like :0:, :1:, etc (because it's inside an iterating component), then you need to realize that updating a specific iteration round is not always supported. See bottom of answer for more detail on that.
Memorize NamingContainer com...
Initializing C# auto-properties [duplicate]
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edited Oct 21 '15 at 12:09
answered Oct 4 '08 at 6:38
Jon...
HTML 5: Is it , , or ?
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edited Feb 19 '16 at 11:40
Manse
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answered Dec...
When should you NOT use a Rules Engine? [closed]
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Cannot push to Heroku because key fingerprint
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How to randomly select rows in SQL?
I am using MSSQL Server 2005. In my db, I have a table "customerNames" which has two columns "Id" and "Name" and approx. 1,000 results.
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How to avoid annoying error “declared and not used”
... clean?
– A-letubby
Feb 13 '14 at 5:06
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