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differentiate null=True, blank=True in django
...mines whether the field will be required in forms. This includes the admin and your custom forms. If blank=True then the field will not be required, whereas if it's False the field cannot be blank.
The combo of the two is so frequent because typically if you're going to allow a field to be blank in...
Java Enum definition
...similar in my C# port of ProtocolBuffers. There are "messages" (immutable) and "builders" (mutable, used to build a message) - and they come as pairs of types. The interfaces involved are:
public interface IBuilder<TMessage, TBuilder>
where TMessage : IMessage<TMessage, TBuilder>
w...
How many characters can a Java String have?
...teger.MAX_VALUE part of the spec of JVM dependant?
– andandandand
Jul 24 '09 at 20:40
6
Integer.M...
How to determine total number of open/active connections in ms sql server 2005
... sys.sysprocesses
WHERE
dbid > 0
GROUP BY
dbid, loginame
And this gives the total:
SELECT
COUNT(dbid) as TotalConnections
FROM
sys.sysprocesses
WHERE
dbid > 0
If you need more detail, run:
sp_who2 'Active'
Note: The SQL Server account used needs the 'sysadmin...
Get properties and values from unknown object
...you should derive from a common base class or implement a common interface and make the calls on those (you can use the as or is operator to help determine which base class/interface you are working with at runtime).
However, if you don't control these type definitions and have to drive logic based...
Ship an application with a database
If your application requires a database and it comes with built in data, what is the best way to ship that application? Should I:
...
How to use SharedPreferences in Android to store, fetch and edit values [closed]
I want to store a time value and need to retrieve and edit it. How can I use SharedPreferences to do this?
31 Answers
...
How should I use try-with-resources with JDBC?
...or the outer try in your example, so you can at least go down from 3 to 2, and also you don't need closing ; at the end of the resource list. The advantage of using two try blocks is that all of your code is present up front so you don't have to refer to a separate method:
public List<User> g...
How do I find which program is using port 80 in Windows? [duplicate]
...
Start menu → Accessories → right click on "Command prompt". In the menu, click "Run as Administrator" (on Windows XP you can just run it as usual), run netstat -anb, and then look through output for your program.
BTW, Skype by default tries to use ports 80 and 443 for i...
How efficient is locking an unlocked mutex? What is the cost of a mutex?
...bunch of mutexes or a single one for an object.
If you have many threads and the access to the object happens often, then multiple locks would increase parallelism. At the cost of maintainability, since more locking means more debugging of the locking.
How efficient is it to lock a mutex? I.e....