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What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
The "N+1 selects problem" is generally stated as a problem in Object-Relational mapping (ORM) discussions, and I understand that it has something to do with having to make a lot of database queries for something that seems simple in the object world.
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quick random row selection in Postgres
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You might want to experiment with OFFSET, as in
SELECT myid FROM mytable OFFSET floor(random()*N) LIMIT 1;
The N is the number of rows in mytable. You may need to first do a SELECT COUNT(*) to figure out the value of N.
Update (by Antony Hatchkins)
You must use floor he...
Getting value of select (dropdown) before change
The thing I want to achieve is whenever the <select> dropdown is changed I want the value of the dropdown before change. I am using 1.3.2 version of jQuery and using on change event but the value I am getting over there is after change.
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In Ruby, is there an Array method that combines 'select' and 'map'?
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I usually use map and compact together along with my selection criteria as a postfix if. compact gets rid of the nils.
jruby-1.5.0 > [1,1,1,2,3,4].map{|n| n*3 if n==1}
=> [3, 3, 3, nil, nil, nil]
jruby-1.5.0 > [1,1,1,2,3,4].map{|n| n*3 if n==1}.compact
=> ...
Define variable to use with IN operator (T-SQL)
... VALUES (2)
INSERT INTO @MyList VALUES (3)
INSERT INTO @MyList VALUES (4)
SELECT *
FROM MyTable
WHERE MyColumn IN (SELECT Value FROM @MyList)
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Why is  appearing in my HTML? [duplicate]
I see this character in Firebug &#65279; .
10 Answers
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Index of Currently Selected Row in DataGridView
It's that simple. How do I get the index of the currently selected Row of a DataGridView ? I don't want the Row object, I want the index (0 .. n).
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How can I generate an MD5 hash?
... “LATIN1” != “ASCII” (or “US-ASCII”). ASCII is a 7-bit character set, Latin1 is an 8-bit character set. They are not the same.
– Bombe
Jan 7 '09 at 7:57
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Is there an onSelect event or equivalent for HTML ?
I have an input form that lets me select from multiple options, and do something when the user changes the selection. Eg,
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How can I escape a double quote inside double quotes?
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Use a backslash:
echo "\"" # Prints one " character.
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