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Overloaded method selection based on the parameter's real type
...
I expect the method selection to take
in consideration the real (not the
declared) parameter type. Am I missing
something?
Yes. Your expectation is wrong. In Java, dynamic method dispatch happens only for the object the method is called ...
How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
...and re-try where necessary.
Some attempted solutions also fail to consider SELECT races. If you try the obvious and simple:
-- THIS IS WRONG. DO NOT COPY IT. It's an EXAMPLE.
BEGIN;
UPDATE testtable
SET somedata = 'blah'
WHERE id = 2;
-- Remember, this is WRONG. Do NOT COPY IT.
INSERT INTO testt...
How many database indexes is too many?
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It depends on the operations that occur on the table.
If there's lots of SELECTs and very few changes, index all you like.... these will (potentially) speed the SELECT statements up.
If the table is heavily hit by UPDATEs, INSERTs + DELETEs ... these will be very slow with lots of indexes since t...
Is there an easy way to attach source in Eclipse?
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Go to Properties (for the Project) -> Java Build Path -> Libraries
Select the Library you want to attach source/javadoc for and then expand it, you'll see a list like so:
Source Attachment: (none)
Javadoc location: (none)
Native library location: (none)
Access rules: (No restrictions)
Sel...
Visual Studio 2013 Missing Convert To Web Application
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It's been moved to the 'Project' menu towards the bottom after selecting the project or folder:
Sources: http://connect.microsoft.com/VisualStudio/feedback/details/806246/visual-studio-2013-web-forms-conver-to-web-applications
...
Xcode “Build and Archive” from command line
... in Xcode 4.4, and I'm sure it was fine in 4.3 as well. Make sure you have selected the correct Xcode release by using xcode-select <path to Xcode.app>
– Reid Ellis
Jul 30 '12 at 18:02
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Is there a CSS parent selector?
How do I select the <li> element that is a direct parent of the anchor element?
33 Answers
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How to disable UITextField editing but still accept touch?
... inputView . Its all good, except that I can edit by copy, paste, cut and select text, and I don't want it. Only the Picker should modify text field.
...
Hidden Features of MySQL
...that has an integer type,
you can also refer to the column as "_rowid" in SELECT statements.
In MySQL, the name of a PRIMARY KEY is PRIMARY
Currently, only InnoDB (v5.1?) tables support foreign keys.
Usually, you create all the indexes you need when you are creating tables.
Any column declared...
Drop columns whose name contains a specific string from pandas DataFrame
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Use the DataFrame.select method:
In [38]: df = DataFrame({'Test1': randn(10), 'Test2': randn(10), 'awesome': randn(10)})
In [39]: df.select(lambda x: not re.search('Test\d+', x), axis=1)
Out[39]:
awesome
0 1.215
1 1.247
2 0.142
3...