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Are there best practices for (Java) package organization? [closed]
... question answered here regarding the fine-grained organization of java packages. For example, my.project.util , my.project.factory , my.project.service , etc.
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Create a date from day month and year with T-SQL
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Cade RouxCade Roux
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How do 20 questions AI algorithms work?
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You can think of it as the Binary Search Algorithm.
In each iteration, we ask a question, which should eliminate roughly half of the possible word choices. If there are total of N words, then we can expect to get an answer after log2(N) ...
Count all occurrences of a string in lots of files with grep
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BombeBombe
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Finding out whether a string is numeric or not
How can we check if a string is made up of numbers only. I am taking out a substring from a string and want to check if it is a numeric substring or not.
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Static and Sealed class differences
... Hossein Narimani RadHossein Narimani Rad
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How to find gaps in sequential numbering in mysql?
...performance.
The (not as fast as possible) answer
Here's version that works on table of any size (not just on 100 rows):
SELECT (t1.id + 1) as gap_starts_at,
(SELECT MIN(t3.id) -1 FROM arrc_vouchers t3 WHERE t3.id > t1.id) as gap_ends_at
FROM arrc_vouchers t1
WHERE NOT EXISTS (SELECT t...
Plot correlation matrix into a graph
...x with some correlation values. Now I want to plot that in a graph that looks more or less like that:
11 Answers
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Find all records which have a count of an association greater than zero
... projects that have an associated vacancy.
UPDATE:
As pointed out by @mackskatz in the comment, without a group clause, the code above will return duplicate projects for projects with more than one vacancies. To remove the duplicates, use
Project.joins(:vacancies).group('projects.id')
UPDATE:
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What is the difference between varchar and nvarchar?
...data. A varchar column is restricted to an 8-bit codepage. Some people think that varchar should be used because it takes up less space. I believe this is not the correct answer. Codepage incompatabilities are a pain, and Unicode is the cure for codepage problems. With cheap disk and memory nowadays...