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What's the difference between identifying and non-identifying relationships?
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An identifying relationship is when the existence of a row in a child table depends on a row in a parent table. This may be confusing because it's common practice these days to create a pseudokey for a child table, but not make...
How to delete duplicates on a MySQL table?
I need to DELETE duplicated rows for specified sid on a MySQL table.
25 Answers
25...
How to concatenate strings of a string field in a PostgreSQL 'group by' query?
... asked for, even letting you specify the delimiter string:
SELECT company_id, string_agg(employee, ', ')
FROM mytable
GROUP BY company_id;
Postgres 9.0 also added the ability to specify an ORDER BY clause in any aggregate expression; otherwise, the order is undefined. So you can now write:
SELEC...
CSS styling in Django forms
...e'> in Django
class MyForm(forms.Form):
myfield = forms.CharField(widget=forms.TextInput(attrs={'class' : 'myfieldclass'}))
or
class MyForm(forms.ModelForm):
class Meta:
model = MyModel
def __init__(self, *args, **kwargs):
super(MyForm, self).__init__(*args, **kwa...
Linq to Entities join vs groupjoin
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Behaviour
Suppose you have two lists:
Id Value
1 A
2 B
3 C
Id ChildValue
1 a1
1 a2
1 a3
2 b1
2 b2
When you Join the two lists on the Id field the result will be:
Value ChildValue
A a1
A a2
A a3
B b1
B b2
When you GroupJoin...
How to customize a Spinner in Android
...d a custom height to the dropdown of a Spinner , say 30dp, and I want to hide the dividers of the dropdown list of Spinner .
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How to create multidimensional array
Can anyone give me a sample/example of JavaScript with a multidimensional array of inputs? Hope you could help because I'm still new to the JavaScript.
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Cast Int to enum in Java
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Try MyEnum.values()[x] where x must be 0 or 1, i.e. a valid ordinal for that enum.
Note that in Java enums actually are classes (and enum values thus are objects) and thus you can't cast an int or even Integer to an enum.
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For each row return the column name of the largest value
...what department they are in most often. It is trivial to tabulate employee ID against department name, but it is trickier to return the department name, rather than the number of roster counts, from the frequency table. A simple example below (column names = departments, row names = employee ids).
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Android: What is android.R.id.content used for?
Anybody could explain the meaning of "android.R.id.content" ?
3 Answers
3
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