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Understanding :source option of has_one/has_many through of Rails
...'ve chosen to namespace the Dog::Breed, because we want to access Dog.find(123).breeds as a nice and convenient association.
Now, if we now want to create a has_many :dog_breeds, :through => :dogs association on Pet, we suddenly have a problem. Rails won't be able to find a :dog_breeds associati...
Is there any difference between GROUP BY and DISTINCT
...ukas Eder
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Cast a Double Variable to Decimal
...hould use the M when declaring a new literal decimal value:
decimal dec = 123.45M;
(Without the M, 123.45 is treated as a double and will not compile.)
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Convert Rows to columns using 'Pivot' in SQL Server
..., 212),
(105, 2, 78),
(109, 2, 97),
(105, 3, 60),
(102, 3, 123),
(101, 3, 220),
(109, 3, 87);
If your values are known, then you will hard-code the query:
select *
from
(
select store, week, xCount
from yt
) src
pivot
(
sum(xcount)
for week in ([1], [2], [3])
) pi...
mysql error 1364 Field doesn't have a default values
...ERO,NO_AUTO_CREATE_USER,NO_ENGINE_UBSTITUTION'
– waza123
Oct 30 '17 at 17:55
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What is a method group in C#?
...) overload which takes a string parameter:
Func<string,string> fn = 123.ToString;
Console.WriteLine(fn("00000000"));
This example picks the ToString() overload which takes no parameters:
Func<string> fn = 123.ToString;
Console.WriteLine(fn());
...
Fastest way to check if a string is JSON in PHP?
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$phone = '021234567'; var_dump(isJson($phone)); return true no! it should return false.
– vee
Jan 2 '14 at 17:12
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TypeScript function overloading
... ...;
var n: number = foo1.bar('baz'); // OK
var s: string = foo1.bar(123); // OK
var a: number[] = foo1.bar([1,2,3]); // ERROR
The actual definition of the function must be singular and perform the appropriate dispatching internally on its arguments.
For example, using a class (which ...
Difference between filter and filter_by in SQLAlchemy
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Be careful when using .filter. a query like id=12345, query(users).filter(id == id) will not filter on users.id. Instead, it will evaluate id == id as True and return all users. You need to use .filter(users.id == id) (as demoed above). I made this mistake earlier today.
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how to change default python version?
...in 8 Apr 28 15:51 pydoc3@ -> pydoc3.2
-rwxrwxr-x 1 root admin 123 Feb 20 11:14 pydoc3.2*
-rwxrwxr-x 2 root admin 25624 Feb 20 11:14 python3*
lrwxr-xr-x 1 root admin 12 Apr 28 15:51 python3-32@ -> python3.2-32
lrwxr-xr-x 1 root admin 16 Apr 28 15:51 python3-config@ -&gt...