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Adding 'serial' to existing column in Postgres
...LTER TABLE foo ALTER COLUMN a SET NOT NULL;
ALTER SEQUENCE foo_a_seq OWNED BY foo.a; -- 8.2 or later
SELECT MAX(a) FROM foo;
SELECT setval('foo_a_seq', 5); -- replace 5 by SELECT MAX result
INSERT INTO foo (b) VALUES('teste');
INSERT INTO bar (b) VALUES('teste');
SELECT * FROM foo;
SELECT * F...
How to reset sequence in postgres and fill id column with new data?
...s no need to specify the WITH 1 anymore. The start value that was recorded by CREATE SEQUENCE or last set by ALTER SEQUENCE START WITH will be used (most probably this will be 1).
Reset the sequence:
ALTER SEQUENCE seq RESTART;
Then update the table's ID column:
UPDATE foo SET id = DEFAULT;
S...
Best way to represent a fraction in Java?
...or denominator.
* Denominator will always be positive (so sign is carried by numerator,
* and a zero-denominator is impossible).
*/
public final class BigFraction extends Number implements Comparable<BigFraction>
{
private static final long serialVersionUID = 1L; //because Number is Seria...
When use getOne and findOne methods Spring Data JPA
...
TL;DR
T findOne(ID id) (name in the old API) / Optional<T> findById(ID id) (name in the new API) relies on EntityManager.find() that performs an entity eager loading.
T getOne(ID id) relies on EntityManager.getReference() that performs an entity lazy loading. So to ensure the effective ...
In which order should floats be added to get the most precise result?
...since you "discard" fewer bits of precision in the smaller value that way. By sorting the numbers, you group values of similar magnitude together, and by adding them in ascending order you give the small values a "chance" of cumulatively reaching the magnitude of the bigger numbers.
Still, if negat...
What is the 'CLSCompliant' attribute in .NET?
... with the CLSCompliant attribute when you want to make sure it can be used by any other .NET language.
These are the basic rules:
Unsigned types should not be part of the public interface of the class. What this means is public fields should not have unsigned types like uint or ulong, public metho...
Sorting related items in a Django template
...property
def sorted_attendee_set(self):
return self.attendee_set.order_by('last_name')
You could define more of these as you need them...
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Why doesn't await on Task.WhenAll throw an AggregateException?
...ceptions and not aggregated exceptions.
-- Edit --
Got it:
An Async Primer by Bill Wagner
Bill Wagner said: (in When Exceptions Happen)
...When you use await, the code generated by the compiler unwraps the
AggregateException and throws the underlying exception. By leveraging
await, you avoid the ex...
Can't seem to discard changes in Git
...s.
core.safecrlf
If true, makes git check if converting CRLF as controlled by
core.autocrlf is reversible. Git will
verify if a command modifies a file in
the work tree either directly or
indirectly. For example, committing a
file followed by checking out the same
file should yield the original file...
SQL injection that gets around mysql_real_escape_string()
...asswd FROM users. In the latter case, the second query is usually executed by use of a UNION clause.
– Jacco
May 21 '12 at 9:47
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