大约有 44,000 项符合查询结果（耗时：0.0416秒） [XML]
Mapping many-to-many association table with extra column(s)
... So I'll show you how it should look like.
If you make the relationships bidirectional, you should thus have
class User {
@OneToMany(mappedBy = "user")
private Set<UserService> userServices = new HashSet<UserService>();
}
class UserService {
@ManyToOne
@JoinColumn(name...
Insert Update trigger how to determine if insert or update
....
Obviously, DELETE triggers can not have "always rows in INSERTED" as I said above
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rails 3 validation on uniqueness on multiple attributes
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In Rails 2, I would have written:
validates_uniqueness_of :zipcode, :scope => :recorded_at
In Rails 3:
validates :zipcode, :uniqueness => {:scope => :recorded_at}
For multiple attributes:
validates :zipcode, :uniqueness => {:scope => [:recor...
MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
as the title says, I want to perform a find (one) for a document, by _id, and if doesn't exist, have it created, then whether it was found or was created, have it returned in the callback.
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Inserting data into a temporary table
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INSERT INTO #TempTable (ID, Date, Name)
SELECT id, date, name
FROM physical_table
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Android: Tabs at the BOTTOM
...about this, but nothing definite.
Is there a way to put the tabs in a TabWidget to the bottom of the screen?
If so, how?
1...
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 ...
Android: Test Push Notification online (Google Cloud Messaging) [closed]
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Found a very easy way to do this.
Open http://phpfiddle.org/
Paste following php script in box. In php script set API_ACCESS_KEY, set device ids separated by coma.
Press F9 or click Run.
Have fun ;)
<?php
// API access key from Google API's Console
define( 'API_ACCE...
Draw on HTML5 Canvas using a mouse
...y = 2;
function init() {
canvas = document.getElementById('can');
ctx = canvas.getContext("2d");
w = canvas.width;
h = canvas.height;
canvas.addEventListener("mousemove", function (e) {
findxy('move', e)
}, false);
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How to get the insert ID in JDBC?
...my case) using JDBC in Java. At the same time, I want to obtain the insert ID. How can I achieve this using JDBC API?
12 An...