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How to find the size of an array in postgresql
...ikely) and are running PostgreSQL 9.4 or higher, you can use cardinality:
SELECT cardinality(id) FROM example;
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ALTER TABLE to add a composite primary key
...dexed from left to right.
For example, consider the following queries:
A) SELECT person, place, thing FROM provider WHERE person = 'foo' AND thing = 'bar';
B) SELECT person, place, thing FROM provider WHERE person = 'foo' AND place = 'baz';
C) SELECT person, place, thing FROM provider WHERE person ...
Missing Push Notification Entitlement
...from the answer given by @Vaiden, in Xcode 8 you can resolve this issue by selecting the target and clicking the "Fix issue". Of course, you'll still need to set up push notifications in the Apple Developer portal (you can simplify the process a little by using the new "Automatically manage signing"...
How to Create Multiple Where Clause Query Using Laravel Eloquent?
...;orWhere($orThose)
->get();
The above will result in such query:
SELECT * FROM users
WHERE (field = value AND another_field = another_value AND ...)
OR (yet_another_field = yet_another_value AND ...)
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How many database indexes is too many?
...
It depends on the operations that occur on the table.
If there's lots of SELECTs and very few changes, index all you like.... these will (potentially) speed the SELECT statements up.
If the table is heavily hit by UPDATEs, INSERTs + DELETEs ... these will be very slow with lots of indexes since t...
How to iterate over arguments in a Bash script
...b of
handling them.
On Unix, a filename (single component) can contain any characters except
slash and NUL '\0'.
However, the shells strongly encourage no spaces or newlines or tabs
anywhere in a path names.
It is also why standard Unix file names do not contain spaces, etc.
When dealing with file ...
Difference between JOIN and INNER JOIN
...nal,
or you can specify CROSS JOIN.
OR
For an inner join, the syntax is:
SELECT ...
FROM TableA
[INNER] JOIN TableB
(in other words, the "INNER" keyword is optional - results are the same
with or without it)
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Func vs. Action vs. Predicate [duplicate]
...s probably most commonly used in LINQ - for example in projections:
list.Select(x => x.SomeProperty)
or filtering:
list.Where(x => x.SomeValue == someOtherValue)
or key selection:
list.Join(otherList, x => x.FirstKey, y => y.SecondKey, ...)
Action is more commonly used for th...
How to get error message when ifstream open fails
...< "opened " << fileName << std::endl;
}
int main(int argc, char* argv[]) {
try {
process(argv[1]);
} catch (const std::system_error& e) {
std::clog << e.what() << " (" << e.code() << ")" << std::endl;
}
return 0;
}
E...
What's the best way to make a d3.js visualisation layout responsive?
...n the window resizes like so:
var aspect = width / height,
chart = d3.select('#chart');
d3.select(window)
.on("resize", function() {
var targetWidth = chart.node().getBoundingClientRect().width;
chart.attr("width", targetWidth);
chart.attr("height", targetWidth / aspect);
});
...