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Difference Between One-to-Many, Many-to-One and Many-to-Many?
...ectional is an engineering decision that trades off memory, processing, performance, etc.
What can be confusing is that a Many-To-Many Bidirectional relationship does not need to be symmetric! That is, a bunch of People could point to a skill, but the skill need not relate back to just those peopl...
Correct use of Multimapping in Dapper
...big caveat here, if the column ordering in the underlying table is flipped for some reason:
ProductID | ProductName | AccountOpened | CustomerName | CustomerId
--------------------------------------- -------------------------
splitOn: CustomerId will result in a null customer name.
If yo...
How to properly create composite primary keys - MYSQL
...rement surrogate primary keys as the ID. info is a table that contains information about both table_1 and table_2 .
8 ...
Why does MYSQL higher LIMIT offset slow the query down?
...able t
ON t.id = q.id
See this article:
MySQL ORDER BY / LIMIT performance: late row lookups
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SELECT * FROM X WHERE id IN (…) with Dapper ORM
...y to write a query with IN clause using Dapper ORM when the list of values for the IN clause is coming from business logic? For example let's say I have a query:
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Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
I'm having a bit of a strange problem. I'm trying to add a foreign key to one table that references another, but it is failing for some reason. With my limited knowledge of MySQL, the only thing that could possibly be suspect is that there is a foreign key on a different table referencing the one I ...
PHP - Extracting a property from an array of objects
...here are 2 solutions:
First (Newer PHP versions)
As @JosepAlsina said before the best and also shortest solution is to use array_column as following:
$catIds = array_column($objects, 'id');
Notice:
For iterating an array containing \stdClasses as used in the question it is only possible with P...
Avoid duplicates in INSERT INTO SELECT query in SQL Server
...the three options, the LEFT JOIN/IS NULL is less efficient. See this link for more details.
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Defining a percentage width for a LinearLayout? [duplicate]
I want to define a percentage width (70%) for a LinearLayout that contains some buttons, so that I can center it and so that the child buttons can fill_parent. Here's a picture showing what I mean:
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Is there a download function in jsFiddle?
... with the CSS, HTML and JS in one file, so you can run it without jsFiddle for debug purposes?
16 Answers
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