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List columns with indexes in PostgreSQL
... uk_test3c unique (c),constraint uk_test3ab unique (a, b));
List indexes and columns indexed:
select
t.relname as table_name,
i.relname as index_name,
a.attname as column_name
from
pg_class t,
pg_class i,
pg_index ix,
pg_attribute a
where
t.oid = ix.indrelid
an...
Random number generator only generating one random number
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Every time you do new Random() it is initialized using the clock. This means that in a tight loop you get the same value lots of times. You should keep a single Random instance and keep using Next on the same instance.
//Function to get a random n...
What's the point of g++ -Wreorder?
...hat somebody might see the list of member initialisers in the constructor, and think that they're executed in that order (j first, then i). They are not, they are executed in the order the members are defined in the class.
Suppose you wrote A(): j(0), i(j) {}. Somebody might read that, and think th...
How do you set the max number of characters for an EditText in Android?
...LengthFilter(MAX_NUM) });
Via xml:
<EditText
android:maxLength="@integer/max_edittext_length"
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How to get the insert ID in JDBC?
...correct, Oracle JDBC driver is still somewhat troublesome with this. MySQL and DB2 already supported it for ages. PostgreSQL started to support it not long ago. I can't comment about MSSQL as I've never used it.
For Oracle, you can invoke a CallableStatement with a RETURNING clause or a SELECT CURR...
Wrong requestCode in onActivityResult
... Just a note: if you use startActivityForResult in a fragment and expect the result from onActivityResult in that fragment, just make sure you call super.onActivityResult in the host activity (in case you override that method there). This is because the activity's onActivityResult seems...
Why NSUserDefaults failed to save NSMutableDictionary in iOS?
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When I need the data, I read out the NSData, and use NSKeyedUnarchiver to convert NSData back to the object.
It is a little cumbersome, because i need to convert to/from NSData everytime, but it just works.
Here is one example per request:
Save:
NSUserDefaults *defaults = [NSUserDefaults stand...
is there a Java equivalent to null coalescing operator (??) in C#? [duplicate]
... answered Mar 7 '11 at 17:36
Andrzej DoyleAndrzej Doyle
95.5k2929 gold badges181181 silver badges224224 bronze badges
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How to check for a valid URL in Java?
...hat you can set to control how this class behaves, by default http, https, and ftp are accepted.
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Multidimensional Array [][] vs [,] [duplicate]
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One is an array of arrays, and one is a 2d array. The former can be jagged, the latter is uniform.
That is, a double[][] can validly be:
double[][] x = new double[5][];
x[0] = new double[10];
x[1] = new double[5];
x[2] = new double[3];
x[3] = new d...