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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...
Font scaling based on width of container
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This is where the so-called element queries come in. Unlike media-queries, element queries would size things based on its containing block, not the viewport, which would be amazing! But unfortunately it doesn't exist yet. However, some polyfills ...
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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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, ...
Linq: What is the difference between Select and Where
...tely different operators acting on IEnumerables.
The first one is what we call a Projection Operator, while the last one is a Restriction Operator.
One interesting way to have insight on the behavior of such operators is to take a look at their "functional type".
Select : (IEnumerable<T1>...
ERROR: Error 1005: Can't create table (errno: 121)
...how, cause I am not familair with it, but it would seem logical if you can call up the constraints, you can delete them too, or alter them.
– Dorvalla
Oct 2 '12 at 7:29
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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 ...
Memcached vs. Redis? [closed]
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Persistence
By default redis persists your data to disk using a mechanism called snapshotting. If you have enough RAM available it's able to write all of your data to disk with almost no performance degradation. It's almost free!
In snapshot mode there is a chance that a sudden crash could result i...
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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