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What is the difference between HashSet and List?
...ady existing in Set
Can perform mathematical set operations against a Set: Union/Intersection/IsSubsetOf etc.
HashSet doesn't implement IList only ICollection
You cannot use indices with a HashSet, only enumerators.
The main reason to use a HashSet would be if you are interested in performing Set ...
Structure padding and packing
...s the following "gaps" into your first structure:
struct mystruct_A {
char a;
char gap_0[3]; /* inserted by compiler: for alignment of b */
int b;
char c;
char gap_1[3]; /* -"-: for alignment of the whole struct in an array */
} x;
Packing, on the other hand prevents compiler ...
How to do a regular expression replace in MySQL?
...ositions and perform substring substitution and extraction, respectively.
SELECT REGEXP_REPLACE('Stackoverflow','[A-Zf]','-',1,0,'c');
-- Output:
-tackover-low
DBFiddle Demo
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How long is the SHA256 hash?
...
you can use this select statement to test it: SELECT length(to_base64(unhex(sha2('say hello to my little friend',256)))) , it is always 44 whatever the length of original string is.
– DrAhmedJava
Apr 9 '...
Why the switch statement cannot be applied on strings?
...however this might not be so easy for strings (considering run-time locale selection and so on). I suppose that such a thing would have to require constexpr cases, or add in unspecified behaviour (never a thing that we want to do).
– M.M
Jun 11 '15 at 23:37
...
Light weight alternative to Hibernate? [closed]
...rt for standard SQL including SQL language features such as UNIONs, nested SELECTs, all types of JOINs, aliasing (e.g. for self-joins), etc
Wide support for non-standard SQL including UDT's, stored procedures, vendor-specific functions, etc.
Read about jOOQ in this article: http://java.dzone.com/a...
Interface type check with Typescript
...mentioned: since TypeScript 2.0, you can even take the advantage of tagged union type.
interface Foo {
type: 'foo';
fooProperty: string;
}
interface Bar {
type: 'bar';
barProperty: number;
}
let object: Foo | Bar;
// You will see errors if `strictNullChecks` is enabled.
if (objec...
Hibernate dialect for Oracle Database 11g?
...e getQuerySequencesString() method, that returns this query:
"select sequence_name from user_sequences;"
for which the execution returns an empty result from database).
Using the dialect org.hibernate.dialect.Oracle9iDialect , or greater, solves the problem, due to a di...
Unpivot with column name
...hould be able to use the following which includes the subject in the final select list:
select u.name, u.subject, u.marks
from student s
unpivot
(
marks
for subject in (Maths, Science, English)
) u;
See SQL Fiddle with demo
...
Java: notify() vs. notifyAll() all over again
...and the difference between these methods right), only one thread is always selected for further monitor acquisition.
That is not correct. o.notifyAll() wakes all of the threads that are blocked in o.wait() calls. The threads are only allowed to return from o.wait() one-by-one, but they each will...