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ALTER TABLE without locking the table?
...ySQL, the whole table is read-locked (allowing concurrent reads, but prohibiting concurrent writes) for the duration of the statement. If it's a big table, INSERT or UPDATE statements could be blocked for a looooong time. Is there a way to do a "hot alter", like adding a column in such a way that th...
SQL JOIN - WHERE clause vs. ON clause
After reading it, this is not a duplicate of Explicit vs Implicit SQL Joins .
The answer may be related (or even the same) but the question is different.
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Can two applications listen to the same port?
...lications on the same machine bind to the same port and IP address? Taking it a step further, can one app listen to requests coming from a certain IP and the other to another remote IP?
I know I can have one application that starts off two threads (or forks) to have similar behavior, but can two ap...
window.onload vs
...d the onload event of the body tag? when do I use which and how should it be done correctly?
13 Answers
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When and how should I use a ThreadLocal variable?
... object (I'm looking at you, SimpleDateFormat). Instead, give each thread its own instance of the object.
For example:
public class Foo
{
// SimpleDateFormat is not thread-safe, so give one to each thread
private static final ThreadLocal<SimpleDateFormat> formatter = new ThreadLocal...
How to check for valid email address? [duplicate]
Is there a good way to check a form input using regex to make sure it is a proper style email address? Been searching since last night and everybody that has answered peoples questions regarding this topic also seems to have problems with it if it is a subdomained email address.
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How to run a shell script in OS X by double-clicking?
...ipt that has user execution permission on OS X, but when I double click on it, it opens in a text editor. How can I get it to run by double-clicking it?
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Repairing Postgresql after upgrading to OSX 10.7 Lion
...n completely borked when trying to connect to the psql server. When I do it from the command line using
15 Answers
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How can I set focus on an element in an HTML form using JavaScript?
I have a web form with a text box in it. How do I go about setting focus to the text box by default?
9 Answers
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Ajax, back button and DOM updates
If javascript modifies DOM in page A, user navigates to page B and then hits back button to get back to the page A. All modifications to DOM of page A are lost and user is presented with version that was originally retrieved from the server.
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