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Does MySQL ignore null values on unique constraints?
... '1' for key 'x'
INSERT table1 VALUES (NULL);
INSERT table1 VALUES (NULL);
SELECT * FROM table1;
Result:
x
NULL
NULL
1
This is not true for all databases. SQL Server 2005 and older, for example, only allows a single NULL value in a column that has a unique constraint.
...
Pointer to class data member “::*”
...unction that would do some pre &post processing before applying a user-selected member function to an object:
void Apply( SomeClass * c, void (SomeClass::*func)() ) {
// do hefty pre-call processing
(c->*func)(); // call user specified function
// do hefty post-call processing
}...
How do I enable MSDTC on SQL Server?
... called 'Distributed Transaction Coordinator' and RIGHT CLICK (on it and
select) > Start.
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In C#, how to check if a TCP port is available?
...s are of server ip and server port you wish to connect to.
The TcpClient selects a transient local port from the available pool to communicate to the server. There's no need to check for the availability of the local port as it is automatically handled by the winsock layer.
In case you can't conn...
Mapping composite keys using EF code first
...f(ColumnAttribute.Order))
.TypedValue.Value ?? 0)
.Select(x => x.Name)
.ToArray();
// apply the keys to the model builder
modelBuilder.Entity(entity.ClrType).HasKey(orderedKeys);
}
I haven't fully tested this in all situations, but it works in my basic t...
Inner text shadow with CSS
...to get your effect.
Since SVG is a subset of XML, SVG text would still be select-able and searchable, and the effect can be produced with less code than Canvas.
It would be harder to achieve this with Canvas because it doesn't have a dom with layers like SVG does.
You could produce the SVG eith...
Restore a postgres backup file using the command line?
...ith pg_restore(1) to
rebuild the database. They allow
pg_restore to be selective about what
is restored, or even to reorder the
items prior to being restored. The
archive file formats are designed to
be portable across architectures.
So depends on the way it was dumped out. You can...
Cannot find JavaScriptSerializer in .Net 4.0
... click References and do Add Reference, then from Assemblies->Framework select System.Web.Extensions.
Now you should be able to add the following to your class file:
using System.Web.Script.Serialization;
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Differences between action and actionListener
...not really useful on command components. They are more useful on input and select components <h:inputXxx>/<h:selectXxx>. In command components, just stick to action and/or actionListener for clarity and better self-documenting code. Moreover, like actionListener, the f:ajax listener does...
ASP.NET Web Site or ASP.NET Web Application?
...e solution is very fast, and you can always click on the Web Site node and select Build, if you’ve made changes.
In an MVC Web Application project you have extra commands and dialogs for common tasks, like ‘Add View’, ‘Go To View’, ‘Add Controller’, etc. These are not available in an ...