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Spring @Transactional - isolation, propagation
...tion
Defines the data contract between transactions.
Read Uncommitted: Allows dirty reads.
Read Committed: Does not allow dirty reads.
Repeatable Read: If a row is read twice in the same transaction, the result will always be the same.
Serializable: Performs all transactions in a sequence.
The...
SQL Joins Vs SQL Subqueries (Performance)?
...explicit JOIN. In my experience IN is a very slow operator, since SQL normally evaluates it as a series of WHERE clauses separated by "OR" (WHERE x=Y OR x=Z OR...).
As with ALL THINGS SQL though, your mileage may vary. The speed will depend a lot on indexes (do you have indexes on both ID column...
CAP theorem - Availability and Partition Tolerance
...een X and Y, so they can't sync updates. At this point you can either:
A) Allow the nodes to get out of sync (giving up consistency), or
B) Consider the cluster to be "down" (giving up availability)
All the combinations available are:
CA - data is consistent between all nodes - as long as all n...
How do I vertically align text in a div?
...; vertical-align: middle;">
<div>
everything is vertically centered in modern IE8+ and others.
</div>
</div>
</div>
It is possible to merge hacks for old browsers (Internet Explorer 6/7) into styles with using # to hide styles from newer brows...
Difference between \n and \r?
...e 10 and 13 respectively;-).
But seriously, there are many:
in Unix and all Unix-like systems, \n is the code for end-of-line, \r means nothing special
as a consequence, in C and most languages that somehow copy it (even remotely), \n is the standard escape sequence for end of line (translated to...
Unix shell script find out which directory the script file resides?
Basically I need to run the script with paths related to the shell script file location, how can I change the current directory to the same directory as where the script file resides?
...
VB.NET - How to move to next item a For Each Loop?
Is there a statment like Exit For , except instead of exiting the loop it just moves to the next item.
6 Answers
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Analyze audio using Fast Fourier Transform
...efficients you get out will be imaginary numbers even though your input is all real values. In order to get the amount of power in each frequency, you need to calculate the magnitude of the FFT coefficient for each frequency. This is not just the real component of the coefficient, you need to calcul...
Doctrine - How to print out the real sql, not just the prepared statement?
...trine is not sending a "real SQL query" to the database server : it is actually using prepared statements, which means :
Sending the statement, for it to be prepared (this is what is returned by $query->getSql())
And, then, sending the parameters (returned by $query->getParameters())
and exe...
Why does int i = 1024 * 1024 * 1024 * 1024 compile without error?
...
@WouterLievens, overflow is normally an "unusual" condition, if not an outright error condition. It is a result of finite-precision math, which most people are not intuitively expecting to happen when they do math. In some cases, like -1 + 1, it's harmless;...