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SQL Server IN vs. EXISTS Performance
...e).
Both forms can be converted to join forms internally, have the join order reversed, and run as loop, hash or merge--based on the estimated row counts (left and right) and index existence in left, right, or both sides.
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Generate Java classes from .XSD files…?
...t(name="Item") indicates that I want to be the root element.
@XmlType(propOrder = {"name", "price"}) indicates the order that I want the element to be arranged in XML output.
@XmlAttribute(name="id", ...) indicates that id is an attribute to root element.
@XmlElement(....) indicates that I want pr...
What is the difference between compile and link function in angularjs
...on this for a couple of days, and I feel that a bit more explanation is in order.
Basically, the docs mention that the separation is largely a performance enhancement. I would reiterate that the compile phase is mainly used when you need to modify the DOM BEFORE the sub-elements themselves are comp...
What's the Android ADB shell “dumpsys” tool and what are its benefits?
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How do I select an entire row which has the largest ID in the table?
... only want one such row, use @MichaelMior's answer,
SELECT row from table ORDER BY id DESC LIMIT 1
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How do I run Redis on Windows?
...dis 2.6 binaries.
So you'll need to download binaries from 2 branches in order to get all the necessary bits. Without further ado, here are the steps:
Download and extract the Redis binaries from the 2.6 branch
Copy all extracted binaries to c:\redis\bin
Create another folder at c:\redis\inst1
D...
Non-alphanumeric list order from os.listdir()
... to process directories of data. Recently, I have noticed that the default order of the lists has changed to something almost nonsensical. For example, if I am in a current directory containing the following subdirectories: run01, run02, ... run19, run20, and then I generate a list from the followin...
How to concatenate strings of a string field in a PostgreSQL 'group by' query?
...e
GROUP BY company_id;
Postgres 9.0 also added the ability to specify an ORDER BY clause in any aggregate expression; otherwise, the order is undefined. So you can now write:
SELECT company_id, string_agg(employee, ', ' ORDER BY employee)
FROM mytable
GROUP BY company_id;
Or indeed:
SELECT str...
Python: List vs Dict for look up table
... be slower for strings, impossible for objects which do not have a natural ordering.
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When annotating a class with @Component, does this mean it is a Spring Bean and Singleton?
...ou may want to annotate it with @Service instead
But have in mind that in order for these annotations to be detected, you need to place this line in applicationContext.xml:
<context:component-scan base-package="com.yourcompany" />
About singletons - spring beans are all in singleton scope ...