大约有 40,000 项符合查询结果（耗时：0.0512秒） [XML]
Should I commit or rollback a read transaction?
...
Suppose I create a temp table, populate it with ids, join it with a data table to select the data that goes with the ids, then delete the temp table. I'm really just reading data, and I don't care what happens to the temp table, since it's temporar...
Function to Calculate Median in SQL Server
... the 7 years since, but personally I wouldn't use this function on a large table until I verified its performance vs. other solutions.
ORIGINAL 2009 POST IS BELOW:
There are lots of ways to do this, with dramatically varying performance. Here's one particularly well-optimized solution, from Median...
How to convert numbers between hexadecimal and decimal
...on from hex to decimal number, you can use the approach with pre-populated table of hex-to-decimal values.
Here is the code that illustrates that idea. My performance tests showed that it can be 20%-40% faster than Convert.ToInt32(...):
class TableConvert
{
static sbyte[] unhex_table =
...
Cleanest way to build an SQL string in Java
...pared statements:
PreparedStatement stm = c.prepareStatement("UPDATE user_table SET name=? WHERE id=?");
stm.setString(1, "the name");
stm.setInt(2, 345);
stm.executeUpdate();
The other thing that can be done is to keep all queries in properties file. For example
in a queries.properties file can ...
Heatmap in matplotlib with pcolor?
...s(np.arange(nba_sort.shape[1]) + 0.5, minor=False)
# want a more natural, table-like display
ax.invert_yaxis()
ax.xaxis.tick_top()
# Set the labels
# label source:https://en.wikipedia.org/wiki/Basketball_statistics
labels = [
'Games', 'Minutes', 'Points', 'Field goals made', 'Field goal attem...
How to make fill height
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position: absolute;
bottom: 0;
right: 0;
}
With the table cell markup like so:
<td class="thatSetsABackground">
<div class="thatSetsABackgroundWithAnIcon">
<dl>
<dt>yada
</dt>
<dd>yada
</dd>
<...
Benchmarking (python vs. c++ using BLAS) and (numpy)
... new machines I also ran the benchmark for matrix sizes 5000 and 8000.
The table below includes the benchmark results from the original answer (renamed: MKL --> Nehalem MKL, Netlib Blas --> Nehalem Netlib BLAS, etc)
Single threaded performance:
Multi threaded performance (8 threads):
T...
How does Go compile so quickly?
...ded to be fast: it should take at most a few seconds to build a large executable on a single computer. To meet these goals required addressing a number of linguistic issues: an expressive but lightweight type system; concurrency and garbage collection; rigid dependency specification; and so on. FAQ
...
Hibernate dialect for Oracle Database 11g?
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Unfortunately does not help for "ORA-01754: a table may contain only one column of type LONG".
– Jan Goyvaerts
Mar 6 '13 at 10:52
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Where does Scala look for implicits?
...s that define which implicits are visible and which are not. The following table showing where the compiler will search for implicits was taken from an excellent presentation about implicits by Josh Suereth, which I heartily recommend to anyone wanting to improve their Scala knowledge. It has been c...