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How enumerate all classes with custom class attribute?
... faster (especially without empirical proof); you've basically written the Select extension method, and the compiler will generate a state machine just as it would if you called Select because of your use of yield return. Finally, any performance gains that might be obtained in the majority of case...
SQL to find the number of distinct values in a column
I can select all the distinct values in a column in the following ways:
11 Answers
11
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How to correct indentation in IntelliJ
...ode → Auto-Indent Lines (default Ctrl + Alt + I) for the current line or selection.
You can customise the settings for how code is auto-formatted under File → Settings → Editor → Code Style.
To ensure comments are also indented to the same level as the code, you can simply do as follows:...
How do I delete a fixed number of rows with sorting in PostgreSQL?
...
You could try using the ctid:
DELETE FROM logtable
WHERE ctid IN (
SELECT ctid
FROM logtable
ORDER BY timestamp
LIMIT 10
)
The ctid is:
The physical location of the row version within its table. Note that although the ctid can be used to locate the row version very quickly,...
Correct use of Multimapping in Dapper
...
I just ran a test that works fine:
var sql = "select cast(1 as decimal) ProductId, 'a' ProductName, 'x' AccountOpened, cast(1 as decimal) CustomerId, 'name' CustomerName";
var item = connection.Query<ProductItem, Customer, ProductItem>(sql,
(p, c) => { p.Cu...
Android device does not show up in adb list [closed]
... Android Nougat: Settings -> Developer options -> Networking -> Select USB Configuration. Changing it to MTP worked for me.
– sffc
Sep 5 '17 at 1:54
6
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SQLite UPSERT / UPDATE OR INSERT
... at this code:
INSERT INTO players (id, name, age)
VALUES (
coalesce((select id from players where user_name='steven'),
(select max(id) from drawings) + 1),
32)
The trick is in coalesce. It returns the id of the user 'steven' if any, and otherwise, it returns a new fresh id.
...
MySQL indexes - what are the best practices?
...t them. Generally I put an index on any fields that I will be searching or selecting using a WHERE clause but sometimes it doesn't seem so black and white.
...
Count Rows in Doctrine QueryBuilder
...
Something like:
$qb = $entityManager->createQueryBuilder();
$qb->select('count(account.id)');
$qb->from('ZaysoCoreBundle:Account','account');
$count = $qb->getQuery()->getSingleScalarResult();
Some folks feel that expressions are somehow better than just using straight DQL. One...
Is #pragma once part of the C++11 standard?
...ifferent developments, the obvious solution is
to generate a lot of random characters for the include guard
when you create it. (A good editor can be set up to do this for
you whenever you open a new header.) But even without this,
I've yet to encounter any problems with conflicts between
librarie...