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When and why are database joins expensive?
...s back to mitigating the size of the working set. Joins involving properly selected keys with correctly set up indexes are cheap, not expensive, because they allow significant pruning of the result before the rows are materialised.
Materialising the result involves bulk disk reads which are the mo...
Remote connect to clearDB heroku database
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In heroku website, go to My Apps and select the app on which you have installed ClearDB.
On the top corner click on Addons and then select ClearDB MySQL Database.
Once there, click on your database and choose the 'Endpoint Information' tab. There you see your ...
SQL-Server: Error - Exclusive access could not be obtained because the database is in use
...WITH REPLACE) in optoins tab at left hand side.
Uncheck all other options.
Select source and destination database.
Click ok.
That's it.
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What is the difference between Left, Right, Outer and Inner Joins?
...ow you begin your query impacts the outcome of the join type. For example, SELECT * FROM students RIGHT OUTER JOIN lockers... would result in a different outcome than SELECT * FROM lockers RIGHT OUTER JOIN students.... Great answer, but would love to see it updated with complete SQL queries
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How to reformat JSON in Notepad++?
...,
"onclick" : "CloseDoc()"
}
]
}
}
}
Tip: Select the code you want to reformat, then Plugins | JSTool | JSFormat.
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Why does using an Underscore character in a LIKE filter give me all the results?
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You have to escape the wildcard character, in sql-server with [] around:
SELECT m.*
FROM Manager m
WHERE m.managerid LIKE '[_]%'
AND m.managername LIKE '%[_]%'
See: LIKE (Transact-SQL)
Demo
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Visual Studio refuses to forget breakpoints?
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Try this select the Breakpoints toolbar item from the Debug toolbar. This brings up the Breakpoints window. From this window, you can view all breakpoints in the application. Here, you select and clear the breakpoint by clicking the D...
Keyboard shortcuts are not active in Visual Studio with Resharper installed
...ou can look at the Visual Studio Integration options for ReSharper by...
Select ReSharper > Options... from the Visual Studio menu
Select the Visual Studio Integration item on the Options window
The bottom of the page gives instructions on how to reset the keyboard scheme.
If that doesn't w...
Is there a way to view past mysql queries with phpmyadmin?
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To view the past queries simply run this query in phpMyAdmin.
SELECT * FROM `general_log`
if it is not enabled, run the following two queries before running it.
SET GLOBAL log_output = 'TABLE';
SET GLOBAL general_log = 'ON';
...
Could not load file or assembly 'System.Web.Mvc'
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In VS2010, right click the project in the Solution Explorer and select 'Add Deployable Dependencies'. Then check the MVC related check boxes in the following dialog.
This creates a '_bin_deployableAssemblies' folder in the project which contains all the .dll files mentioned in other answ...