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Should functions return null or an empty object?
...value that is universally defined as "no data". That's like stating that a SQL database should return an error if a where clause produces no results. While an Exception is a valid design choice (though one that would irritate me as a consumer), it's not any "more correct" than returning null. And no...
Servlet for serving static content
...y project. The only method you need is coalesce (which is identical to the SQL function COALESCE). This is the code:
public static <T> T coalesce(T...ts) {
for(T t: ts)
if(t != null)
return t;
return null;
}
...
postgresql return 0 if returned value is null
...re NULL values in the query.
For all versions I've tested, postgres and mysql will ignore all NULL values when averaging, and it will return NULL if there is nothing to average over. This generally makes sense, as NULL is to be considered "unknown". If you want to override this you can use coalesc...
Preventing Laravel adding multiple records to a pivot table
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@alexandre Butynsky method works very well but use two sql queries.
One to check if cart contains the item and one to save.
To use only one query use this:
try {
$cart->items()->save($newItem);
}
catch(\Exception $e) {}
...
WebSockets vs. Server-Sent events/EventSource
..., or other automated data push mechanisms (e.g. updating a client-side Web SQL Database or IndexedDB object store). If you'll need to send data to a server, XMLHttpRequest is always a friend.
SSEs are sent over traditional HTTP. That means they do not require a special protocol or server implem...
How to select different app.config for several build configurations
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$(ProjectDir)App.Config.Settings.xls
MachineName ConfigFilePath SQLServer
default App.config DEVSQL005
Test App.config TESTSQL005
UAT App.config UATSQL005
Production App.config PRODSQL005
YourLocalMachine ...
Multiple queries executed in java in single statement
... as it currently provides an exception even though it is possible in the MySQL query browser.
6 Answers
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In C#, how do I calculate someone's age based on a DateTime type birthday?
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Actually this is great for usage on MS-SQL with datetime-fields (total days since 01-011900)
– Patrik
Jul 3 '15 at 12:01
5
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Difference between HBase and Hadoop/HDFS
This is kind of naive question but I am new to NoSQL paradigm and don't know much about it. So if somebody can help me clearly understand difference between the HBase and Hadoop or if give some pointers which might help me understand the difference.
...
Why does this assert throw a format exception when comparing structures?
...en't expecting foo nor was the actual value bar!
Basically this is like a SQL injection attack, but in the rather less scary context of string.Format.
As a workaround, you can use string.Formatas StriplingWarrior suggests. That avoids the second level of formatting being performed on the result of...