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What is the difference between “JPG” / “JPEG” / “PNG” / “BMP” / “GIF” / “TIFF” Image?
...ey are exact representations of the image. Bitmap formats such as BMP generally are uncompressed, although there also are compressed BMP files as well.
Lossy compression formats are generally suited for photographs. It is not suited for illustrations, drawings and text, as compression artifacts fro...
When to use Common Table Expression (CTE)
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I use them to break up complex queries, especially complex joins and sub-queries. I find I'm using them more and more as 'pseudo-views' to help me get my head around the intent of the query.
My only complaint about them is they cannot be re-used. For example, I may have...
Make virtualenv inherit specific packages from your global site-packages
...ch will contain just some libraries (which i chose) of the base python installation.
4 Answers
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Determine which MySQL configuration file is being used
...inux, then start the 'mysqld' with strace, for eg strace ./mysqld.
Among all the other system calls, you will find something like:
stat64("/etc/my.cnf", 0xbfa3d7fc) = -1 ENOENT (No such file or directory)
stat64("/etc/mysql/my.cnf", {st_mode=S_IFREG|0644, st_size=4227, ...}) = 0
open("/etc/...
Apache Spark: The number of cores vs. the number of executors
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To hopefully make all of this a little more concrete, here’s a worked example of configuring a Spark app to use as much of the cluster as
possible: Imagine a cluster with six nodes running NodeManagers, each
equipped with 16 cores and 64GB o...
How to “undelete” a deleted folder in Subversion / TortoiseSVN?
We have accidentally deleted the 'tags' folder from our Subversion repository where we only intended to delete one specific tag. What is the easiest way to get the 'tags' folder back?
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Android SharedPreference security
... within the app's data directory with filesystem permissions set that only allow the UID that the specific application runs with to access them. So, they are private in so much as Linux file permissions restrict access to them, the same as on any Linux/Unix system.
Anyone with root level access to ...
Application Loader: “Cannot proceed with delivery: an existing transporter instance is currently upl
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Basically, you need to clear out the transport tokens. This can happen if you were to close out of Xcode while in the middle of submitting an app to iTunes Connect.
The token files now appear in the
Library/Caches/com.apple.amp.i...
Can a foreign key be NULL and/or duplicate?
...at field must exist first in a different table (the parent table). That is all an FK is by definition. Null by definition is not a value. Null means that we do not yet know what the value is.
Let me give you a real life example. Suppose you have a database that stores sales proposals. Suppose furth...
CSS Background Opacity [duplicate]
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It's not really correct to say that "Children inherit opacity". They don't. It's just that if a child is contained in a parent with opacity, the child will have opacity: 1, but the parent applies it's opacity to itself including all it'...