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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...
Table Naming Dilemma: Singular vs. Plural Names [closed]
...
Customer
Customer.CustomerID
CustomerAddress
public Class Customer {...}
SELECT FROM Customer WHERE CustomerID = 100
Once you know you are dealing with "Customer", you can be sure you will use the same word for all of your database interaction needs.
Reason 5. (Globalization). The world is gettin...
Changing navigation bar color in Swift
...UIColor.whiteColor()
UINavigationBar.appearance().barTintColor = Style.SELECTED_COLOR
UINavigationBar.appearance().translucent = false
UINavigationBar.appearance().clipsToBounds = false
UINavigationBar.appearance().backgroundColor = Style.SELECTED_COLOR
UINavigationBar.appearance...
Xcode 4 - “Archive” is greyed out?
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You have to select the device in the schemes menu in the top left where you used to select between simulator/device. It won’t let you archive a build for the simulator.
Or you may find that if the iOS device is already selected the ar...
How do I stop Chrome from yellowing my site's input boxes?
...e property to none.
input[type="text"], input[type="password"], textarea, select {
outline: none;
}
In cases where the browser may add a background color as well this can be fixed by something like
:focus { background-color: #fff; }
...
IntelliJ IDEA JDK configuration on Mac OS
...Home
In IDEA you can configure the new JSDK in File | Project Structure, select SDKs on the left, then press [+] button, then specify the above JDK home path, you should get something like this:
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How can I use external JARs in an Android project?
...your JAR files to the libs folder
Now right click on the Jar file and then select Build Path > Add to Build
Path, which will create a folder called 'Referenced Libraries' within your
project
By doing this, you will not
lose your libraries that are being referenced on your
hard drive whenever you...
GROUP_CONCAT ORDER BY
...
You can use ORDER BY inside the GROUP_CONCAT function in this way:
SELECT li.client_id, group_concat(li.percentage ORDER BY li.views ASC) AS views,
group_concat(li.percentage ORDER BY li.percentage ASC)
FROM li GROUP BY client_id
...
How do I get the collection of Model State Errors in ASP.NET MVC?
...he ModelState, use this Linq:
var modelStateErrors = this.ModelState.Keys.SelectMany(key => this.ModelState[key].Errors);
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How to access a mobile's camera from a web app?
...re="capture" (Boolean) . The attribute is used to force capture instead of selecting from the library. See the spec and Correct Syntax for HTML Media Capture
– Octavian Naicu
Nov 9 '16 at 15:56
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