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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...
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;
share
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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, ...
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 ...
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 ...
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.
share
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imp...
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 use GROUP BY to concatenate strings in SQL Server?
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[Note: This solution only works on SQL 2005 and later. Original question didn't specify the version in use.]
CREATE TABLE #YourTable ([ID] INT, [Name] CHAR(1), [Value] INT)
INSERT INTO #YourTable ([ID],[Name],[Value]) VALUES (1,'A',4)
INSERT INTO #YourTable ([ID],[Name],[Value]) VALUES (1,'B',8)
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