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Difference between natural join and inner join
... definition of a natural join is to join on *all like-named columns*. From MySQL doc: The NATURAL [LEFT] JOIN of two tables is defined to be semantically equivalent to an INNER JOIN or a LEFT JOIN with a USING clause that names all columns that exist in both tables.. And another thing - in practice ...
Serializing object that contains cyclic object value
...which is objects with the special $ref property. Let's see how that works.
root = makeToolshed();
[root.bolt === root.nut.needs, root.nut.needs.needs === root.nut]; // retutrns [true,true]
The dollar sign stands for the root. .bolt having $ref tells us that .bolt is an "already seen" object, and th...
SQL Server: SELECT only the rows with MAX(DATE)
...
For MySql you can do something like the following:
select OrderNO, PartCode, Quantity from table a
join (select ID, MAX(DateEntered) from table group by OrderNO) b on a.ID = b.ID
...
Getting View's coordinates relative to the root layout
Can I get a View's x and y position relative to the root layout of my Activity in Android?
10 Answers
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How to make a SIMPLE C++ Makefile
...nix, the executables don't have any extensions.
One thing to note is that root-config is a utility which provides the right compilation and linking flags; and the right libraries for building applications against root. That's just a detail related to the original audience for this document.
Make M...
What Process is using all of my disk IO
...s axu | awk '{if (\$8==\"D\") {print \$0}}'"
Wed Aug 29 13:00:46 CLT 2012
root 321 0.0 0.0 0 0 ? D May28 4:25 \_ [jbd2/dm-0-8]
Wed Aug 29 13:00:47 CLT 2012
Wed Aug 29 13:00:48 CLT 2012
Wed Aug 29 13:00:49 CLT 2012
Wed Aug 29 13:00:50 CLT 2012
root 321 0.0 0.0 ...
When to use SELECT … FOR UPDATE?
...ends on the concurrency control your database system is using.
MyISAM in MySQL (and several other old systems) does lock the whole table for the duration of a query.
In SQL Server, SELECT queries place shared locks on the records / pages / tables they have examined, while DML queries place update ...
How to efficiently build a tree from a flat structure?
...t AssociatedObject { get; set; }
}
IEnumerable<Node> BuildTreeAndGetRoots(List<MyObject> actualObjects)
{
Dictionary<int, Node> lookup = new Dictionary<int, Node>();
actualObjects.ForEach(x => lookup.Add(x.ID, new Node { AssociatedObject = x }));
foreach (var ...
Clone private git repo with dockerfile
...
# Install software
RUN apt-get install -y git
# Make ssh dir
RUN mkdir /root/.ssh/
# Copy over private key, and set permissions
# Warning! Anyone who gets their hands on this image will be able
# to retrieve this private key file from the corresponding image layer
ADD id_rsa /root/.ssh/id_rsa
#...
How does Java Garbage Collection work with Circular References?
... if they aren't reachable through a chain starting at a garbage collection root, so these objects will be collected. Even though objects may point to each other to form a cycle, they're still garbage if they're cut off from the root.
See the section on unreachable objects in Appendix A: The Truth ...