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What is PostgreSQL explain telling me exactly?
...ly 1 sentence of technical content: "• EXPLAIN works on any DML not just SELECT (ie UPDATE, DELETE, and INSERT)". My biggest misunderstanding is what "startup" time means, and that's not explained anywhere in these ~30 slides.
– Mark E. Haase
Feb 19 '16 at 15...
Func vs. Action vs. Predicate [duplicate]
...s probably most commonly used in LINQ - for example in projections:
list.Select(x => x.SomeProperty)
or filtering:
list.Where(x => x.SomeValue == someOtherValue)
or key selection:
list.Join(otherList, x => x.FirstKey, y => y.SecondKey, ...)
Action is more commonly used for th...
bash: mkvirtualenv: command not found
...erage the chance that virtualenvwrapper.sh is already in your shell's PATH and just issue a source `which virtualenvwrapper.sh`
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How to get database structure in MySQL via query
...CHEMA.TABLES table. It contains metadata about all your tables.
Example:
SELECT * FROM `INFORMATION_SCHEMA`.`TABLES`
WHERE TABLE_NAME LIKE 'table1'
The advantage of this over other methods is that you can easily use queries like the one above as subqueries in your other queries.
...
Android emulator-5554 offline
...ll search for ports in use starting with 565. Execute: netstat -a -n -o | Select-String ":565"
PS C:\Users\CJBS> netstat -a -n -o | Select-String ":565"
TCP 127.0.0.1:5653 127.0.0.1:5653 ESTABLISHED 5944
TCP 127.0.0.1:5657 127.0.0.1:5657 ESTABL...
Can you build dynamic libraries for iOS and load them at runtime?
... time this question was asked, Dynamic libraries were not supported by iOS and will result in your app getting rejected. Only static libraries are allowed.
However, in iOS8 you can use dynamic libraries and frameworks. It should "just work"
...
Count lines of code in all java classes in Android Studio
...all the latest version
To install
Run Android Studio
From the menu bar, select File-->Settings
Under IDE Settings, click Plugins, and then click Install plugin from disk
Navigate to the folder where you downloaded the plugin and double-click it
Restart Android Studio
To count the lines
Che...
Renaming xcode 4 project and the actual folder
...e, click the icon shown in the screenshot below to bring up a file dialog. Select the folder that you previously renamed. This will re-associate the virtual folder with the real folder on disk, and will automatically fix the links to all the files inside.
In your build settings, search for the old f...
What are the differences between 'call-template' and 'apply-templates' in XSL?
...ower of XSLT: It takes any number of XML nodes (whatever you define in the select attribute), iterates them (this is important: apply-templates works like a loop!) and finds matching templates for them:
<!-- sample XML snippet -->
<xml>
<foo /><bar /><baz />
</xml...
Aggregate function in an SQL update query?
...
UPDATE t1
SET t1.field1 = t2.field2Sum
FROM table1 t1
INNER JOIN (select field3, sum(field2) as field2Sum
from table2
group by field3) as t2
on t2.field3 = t1.field3
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