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Rails where condition using NOT NIL
..., so you really should just use the joins predicate:
Foo.joins(:bar)
Select * from Foo Inner Join Bars ...
But, for the record, if you want a "NOT NULL" condition simply use the not predicate:
Foo.includes(:bar).where.not(bars: {id: nil})
Select * from Foo Left Outer Join Bars on .. WHERE ...
How to store arrays in MySQL?
... retrieve a person and all of their fruit you can do something like this:
SELECT p.*, f.*
FROM person p
INNER JOIN person_fruit pf
ON pf.person_id = p.id
INNER JOIN fruits f
ON f.fruit_name = pf.fruit_name
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Blocks and yields in Ruby
...y:
days = ["monday", "tuesday", "wednesday", "thursday", "friday"]
# select those which start with 't'
days.select do | item |
item.match /^t/
end
=> ["tuesday", "thursday"]
Or, we can also provide a custom sort algorithm, for instance based on the string size:
days.sort do |x,...
JPA EntityManager: Why use persist() over merge()?
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I noticed that when I used em.merge, I got a SELECT statement for every INSERT, even when there was no field that JPA was generating for me--the primary key field was a UUID that I set myself. I switched to em.persist(myEntityObject) and got just INSERT statements then...
Is there a use-case for singletons with database access in PHP?
...all one needs to maintain multiple database connections, multiple database selections, multiple database queries, multiple result sets in a given singleton is just keeping them in variables/arrays in the singleton as long as they are needed. This can be as simple as keeping them in arrays, though yo...
Can I have multiple primary keys in a single table?
...hese practices, but there is nothing in the relational model that requires selecting a primary key among the candidate keys.
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JQuery - find a radio button by value
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Try this:
$(":radio[value=foobar]")
This will select all radio buttons with the attribute value="foobar".
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CodeFile vs CodeBehind
...bute of the Page directive or is there a way to create a web project which selects codebehind or codefile, by default, each time a new web page is added?
– Matt W
Nov 5 '09 at 8:42
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Using NumberPicker Widget with Strings
...wrap true or false, try it you will know the difference
pickers.setWrapSelectorWheel(false);
//create button to test selected text string
btnPicker.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//get position (int)...
Method has the same erasure as another method in type
... template methods, but yeah: the compiler makes sure the right method gets selected before type erasure. Beautiful. If it weren't tainted by the legacy code compatibility issues.
– Jonas Eicher
Dec 5 '12 at 9:03
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