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Rails: Adding an index after adding column
...able < ActiveRecord::Migration
def change
add_index :table, :user_id
end
end
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Best design for a changelog / auditing database table? [closed]
...rted from the very minimalistic design, like the one you described:
event ID
event date/time
event type
user ID
description
The idea was the same: to keep things simple.
However, it quickly became obvious that this minimalistic design was not sufficient. The typical audit was boiling down to qu...
Is there a command to list all Unix group names? [closed]
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Yes MichaelIT is right the groups command did not list all groups. I asked this because unsure if there is a simple command like groups to lists all groups names or even a swith to it like groups [-a|--all] to list all system groups without doing file scan.
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Splitting string into multiple rows in Oracle
...i can you please clarify me why the above query gives duplicate rows if i didn't use distinct keyword in query
– Jagadeesh G
Sep 12 '13 at 16:50
2
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WHERE vs HAVING
...level aliases in GROUP BY, ORDER BY and HAVING.
And are there any downsides instead of doing "WHERE 1" (writing the whole definition instead of a column name)
If your calculated expression does not contain any aggregates, putting it into the WHERE clause will most probably be more efficient.
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How to link a Facebook app with an existing fan page
... The key is making sure App Page is the ONLY category. We had "Video Game" and "App Page" and this didn't work until we removed "Video Game." As an aside Facebook's workflow is insane--almost like it was written by a 19-year-old in his dorm room.
– Mike Pandolfini
...
How do I use the conditional operator (? :) in Ruby?
...some extra junk after it), but they are not required in the last case as said issue does not arise.
You can use the "long-if" form for readability on multiple lines:
question = if question.size > 20 then
question.slice(0, 20) + "..."
else
question
end
...
How to link to a named anchor in Multimarkdown?
...er to it on the same page by [link text](#abcd).
(This uses name= and not id=, for reasons explained in this answer.)
Remote references can use [link text](http://...#abcd) of course.
This works like a dream, provided you have control over the source and target texts. The anchor can even appear i...
How to run an EXE file in PowerShell with parameters with spaces and quotes
...ync -source:dbfullsql="Data Source=mysource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;" -dest:dbfullsql="Data Source=.\mydestsource;Integrated Security=false;User ID=sa;Pwd=sapass!;Database=mydb;",computername=10.10.10.10,username=administrator,password=adminpass
Arg 0 is <-...
JPA: How to have one-to-many relation of the same Entity type
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Yes, this is possible. This is a special case of the standard bidirectional @ManyToOne/@OneToMany relationship. It is special because the entity on each end of the relationship is the same. The general case is detailed in Section 2.10.2 of the JPA 2.0 spec.
Here's a worked example. F...