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Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
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Quite likely your sourcecodes_tags table contains sourcecode_id values that no longer exists in your sourcecodes table. You have to get rid of those first.
Here's a query that can find those IDs:
SELECT DISTINCT sourcecode_id FROM
sourcecodes_tags tags LEFT JOIN sourcecodes sc ON...
Calendar Recurring/Repeating Events - Best Storage Method
...store repeating/recurring event information as efficiently as possibly. I didn't want to have a large number of rows, and I wanted to easily lookup all events that would take place on a specific date.
The method below is great at storing repeating information that occurs at regular intervals, such ...
How do I add a Fragment to an Activity with a programmatically created content view
...han one problem with that code. A fragment cannot be declared that way, inside the same java file as the activity but not as a public inner class. The framework expects the fragment's constructor (with no parameters) to be public and visible. Moving the fragment into the Activity as an inner class, ...
How do I change an HTML selected option using JavaScript?
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Change
document.getElementById('personlist').getElementsByTagName('option')[11].selected = 'selected'
to
document.getElementById('personlist').value=Person_ID;
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no gravity for scrollview. how to make content inside scrollview as center
I want the content inside the scrollView as center.
7 Answers
7
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Why does MYSQL higher LIMIT offset slow the query down?
...ecords. It needs to check and count each record on its way.
Assuming that id is a PRIMARY KEY of a MyISAM table, you can speed it up by using this trick:
SELECT t.*
FROM (
SELECT id
FROM mytable
ORDER BY
id
LIMIT 10000, 30
) q
JOIN ...
Get Specific Columns Using “With()” Function in Laravel Eloquent
... Post::with(array('user'=>function($query){
$query->select('id','username');
}))->get();
It will only select id and username from other table. I hope this will help others.
Remember that the primary key (id in this case) needs to be the first param in the
$query->select() ...
Remove duplicates in the list using linq
I have a class Items with properties (Id, Name, Code, Price) .
11 Answers
11
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SQL select only rows with max value on a column [duplicate]
...All you need is a GROUP BY clause with the MAX aggregate function:
SELECT id, MAX(rev)
FROM YourTable
GROUP BY id
It's never that simple, is it?
I just noticed you need the content column as well.
This is a very common question in SQL: find the whole data for the row with some max value in a co...
How to iterate object in JavaScript? [duplicate]
...in the array.
var data = dictionary.data;
for (var i in data)
{
var id = data[i].id;
var name = data[i].name;
}
You can follow similar approach to iterate the image array.
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