According to [RFC 5321][1], forward and reverse path can be up to 256 chars long, so the email address can be up to 254 characters long. You&#39;re safe with using 255 chars.


  [1]: https://www.rfc-editor.org/rfc/rfc5321

[RFC5321][1] and [RFC5322][2], the relevant standards for SMTP, specify that an address consists of a local part and a domain. They further state that the maximum sizes for those are respectively 64 and 253 octets, though there&#39;s a further 256-octet limit imposed by the forward and reverse paths, including the punctuation (so 254 in reality).

So that should be all that you need for that.

  [1]: https://www.rfc-editor.org/rfc/rfc5321
  [2]: https://www.rfc-editor.org/rfc/rfc5322

standard in any enterprise web application is varchar with 255 length

      varchar(255)

Using VARCHAR 255 is probably the best idea here - there is nothing lost in giving few more bytes for each email address. 255 is also large enough to avoid cutting any sane email address.

Well varchar (255) is a standard for me. And i think it is good approach to store emails.

https://stackoverflow.com/questions/386294/maximum-length-of-a-valid-email-id

you should use varchar field,  
which make the size does not matter (assuming you are not building an index on it)

Following [this question][1], I am trying to implement an async method using the TPL, and trying to follow TAP guidelines.

I want my async method to perform a callback when it&#39;s finished. As far as I can see there are three ways I can do this.

1) Callback manually in my task delegate

    public Task DoWorkAsync(DoWorkCompletedCallback completedCallback)
    {
        return Task.Factory.StartNew(
        { 
            //do work
    
            //call callback manually
            completedCallback();
        });
    }

2) Assign callback to task in task delegate

    public Task DoWorkAsync(DoWorkCompletedCallback completedCallback)
    {
        return Task.Factory.StartNew(
        { 
            //do work
        }
        ).ContinueWith(completedCallback); //assign callback to Task
    }

3) Assign callback to task in caller

    public Task DoWorkAsync()
    {
        return Task.Factory.StartNew(
        { 
            //do work
        });
    }
    
    public void SomeClientCode()
    {
        Task doingWork = DoWorkAsync();
        doingWork.ContinueWith(OnWorkCompleted);
    }

My gut feeling is that 3 is more correct, because it decouples the callback from the method, and means that client code can manage the task any way it sees fit (using callbacks, polling etc), which seems to be what Tasks are all about. However, what happens if DoWorkAsync() completes its work before the client code hooks up its callback?

Is there a generally accepted way to do this or is it all too new?

Is there any advantage of doing 2) over 1)?

  [1]: https://stackoverflow.com/questions/8240316/advantages-of-using-standard-net-async-patterns

Where to define callback for Task based asynchronous method

I know there are a lot of examples using the mailto: post action to send emails using just html forms.

But using this will actually popup the send email dialog box e.g. outlook dialog box. And it actually uses our own smtp server to send the email.

Is there any way to create html forms that will simply send email upon submission?

Is there a javascript api which can achieve this effect? Say for example node.js?

Can anyone provide some code samples?

How to create an email form that can send email using html

&gt; **Possible Duplicate:**  
&gt; [Common mySQL fields and their appropriate data types](https://stackoverflow.com/questions/354763/common-mysql-fields-and-their-appropriate-data-types)  
&gt; [What are the recommended database column sizes for names?](https://stackoverflow.com/questions/512614/what-are-the-recommended-database-column-sizes-for-names)  

&lt;!-- End of automatically inserted text --&gt;

I am looking for what would be the most correct field type and size to store email address into a mysql table.

I was initially considering varchar 255 but I think 255 might be too much or even too little what is the average size where I would be able to catch all kinda of valid email address ?

Acceptable field type and size for email address?

> Possible Duplicate: 
> <a href="https://stackoverflow.com/questions/354763/common-mysql-fields-and-their-appropriate-data-types" target="_blank" rel="noopener noreferrer">Common mySQL fields and their appropriate data types</a> 
> <a href="https://stackoverflow.com/questions/512614/what-are-the-recommended-database-column-sizes-for-names" target="_blank" rel="noopener noreferrer">What are the recommended database column sizes for names?</a>

I am looking for what would be the most correct field type and size to store email address into a mysql table.
I was initially considering varchar 255 but I think 255 might be too much or even too little what is the average size where I would be able to catch all kinda of valid email address ?

I am using prepared statements to execute mysql database queries. And I want to implement a search functionality based on a keyword of sorts. 

For that I need to use `LIKE` keyword, that much I know. And I have also used prepared statements before, but I do not know how to use it with `LIKE` because from the following code where would I add the `&#39;keyword%&#39;`? 

Can I directly use it in the `pstmt.setString(1, notes)` as `(1, notes+&quot;%&quot;)` or something like that. I see a lot of posts on this on the web but no good answer anywhere.

    PreparedStatement pstmt = con.prepareStatement(
          &quot;SELECT * FROM analysis WHERE notes like ?&quot;);
    pstmt.setString(1, notes);
    ResultSet rs = pstmt.executeQuery();

Using &quot;like&quot; wildcard in prepared statement

I have to retrieve a MySQL database information from master database and then connect to that database, and fetch some records.

I mean that holding one database I want to load another database.

Is it possible with Codeigniter? Right now I&#39;m using following lines of code in my model.

    function connectDb($credential)
	{
		
		$config[&#39;hostname&#39;] = $credential[&#39;server&#39;];
		$config[&#39;username&#39;] = $credential[&#39;username&#39;];
		$config[&#39;password&#39;] = $credential[&#39;password&#39;];
		$config[&#39;database&#39;] = $credential[&#39;database&#39;];
		$config[&#39;dbdriver&#39;] = &quot;mysql&quot;;
		$config[&#39;dbprefix&#39;] = &quot;&quot;;
		$config[&#39;pconnect&#39;] = FALSE;
		$config[&#39;db_debug&#39;] = TRUE;
		$config[&#39;cache_on&#39;] = FALSE;
		$config[&#39;cachedir&#39;] = &quot;&quot;;
		$config[&#39;char_set&#39;] = &quot;utf8&quot;;
		$config[&#39;dbcollat&#39;] = &quot;utf8_general_ci&quot;;

		$DB2=$this-&gt;load-&gt;database($config);
		
		$DB2-&gt;db-&gt;select(&#39;first_name,last_name&#39;);
		$query = $DB2-&gt;db-&gt;get(&#39;person&#39;);
		print_r($query);
		
	}

its not working is there any other way?




Codeigniter - multiple database connections

    Show Database
    Use database
    show tables
    Describe &lt;table&gt;

All good and well, but is it possible to show the current connections host.
Not connection_id, but the IP Address or Name of the host.

Show MySQL host via SQL Command

&gt; **Possible Duplicate:**  
&gt; [mysql datatype for telephne number and address](https://stackoverflow.com/questions/1846254/mysql-datatype-for-telephne-number-and-address)  

&lt;!-- End of automatically inserted text --&gt;

Any suggestions on best practice to store telephone numbers in a DB? Consider a US phone number:

 - 555 555 1212
 - 555-555-1212
 - (555) 555 1212
 - 5555551212
 - 1-555-555-1212
 - 1 (555) 555-1212
 - and so on ...

Should I remove formatting and store only numbers? Should I just use one field -- or split them up into: country code, area code, phone number, etc.? Suggestions?

How to store phone numbers on MySQL databases?

Every time is set up a new SQL table or add a new `varchar` column to an existing table, I am wondering one thing: what is the best value for the `length`. 

So, lets say, you have a column called `name` of type `varchar`. So, you have to choose the length. I cannot think of a name &gt; 20 chars, but you will never know. But instead of using 20, I always round up to the next 2^n number. In this case, I would choose 32 as the length. I do that, because from an computer scientist point of view, a number 2^n looks more `even` to me than other numbers and I&#39;m just assuming that the architecture underneath can handle those numbers slightly better than others.

On the other hand, MSSQL server for example, sets the default length value to 50, when you choose to create a varchar column. That makes me thinking about it. Why 50? is it just a random number, or based on average column length, or what?

It could also be - or probably is - that different SQL servers implementations (like MySQL, MSSQL, Postgres, ...) have different best column length values.



Best practices for SQL varchar column length

The [Android Documentation says][1] that there is two sizes for a view, the *measured dimensions* and the *drawing dimensions*. The measured dimension is the one computed in the *measure pass* (the [onMeasure][2] method), while the *drawing dimensions* are the actual size on screen. Particularly, the documentation says that:

&gt; These values may, but do not have to, be different from the measured width and height.

So, my question is: what could make the drawing dimension be different of the measured dimension? If the [onMeasure(int,int)][3] method respects the layout requirements (given as the parameters *widthMeasureSpec* and *heightMeasureSpec*, how could the SDK decides that the view should have a different drawing size?

Additionally, how/where in the [Android Source Code][4] the measured width/height is used to compute the drawing width/height? I tryed to look into the [View source code][5], but I can&#39;t figure out how the measuredWidth/Height is used to compute the final width/height. Maybe it has something to do with the padding, but I&#39;m not sure.


  [1]: http://developer.android.com/reference/android/view/View.html#SizePaddingMargins
  [2]: http://developer.android.com/reference/android/view/View.html#onMeasure%28int,%20int%29
  [3]: http://developer.android.com/reference/android/view/View.html#onMeasure%28int,%20int%29
  [4]: https://github.com/android
  [5]: https://github.com/android/platform_frameworks_base/blob/master/core/java/android/view/View.java

What is the difference between getWidth/Height() and getMeasuredWidth/Height() in Android SDK?

I&#39;m wondering if I can know how long in bytes for a `string` in C#, anyone know?

How to know the size of the string in bytes?

Lets say I have mongo documents like this:

**Question 1**

    {
        answers:[
           {content: &#39;answer1&#39;},
           {content: &#39;2nd answer&#39;}
        ]
    }


**Question 2**

    {
        answers:[
           {content: &#39;answer1&#39;},
           {content: &#39;2nd answer&#39;}
           {content: &#39;The third answer&#39;}
        ]
    }

Is there a way to order the collection by size of answers? 

After a little research I saw suggestions of adding another field, that would contain number of answers and use it as a reference but may be there is native way to do it?

Mongo order by length of array

I have apache with `mod_deflate` enabled. I would like to find out the size of the page with `mod_deflate` enabled and without, and compare how much performance is achieved in size. In curl, I seem to ask server for gzipped content using `--compressed` and to send the normal, but can&#39;t seem to find the size of that page. Any idea how to do that?

`curl --head http://site`

    HTTP/1.1 200 OK
    Date: Wed, 08 Feb 2012 08:48:04 GMT
    Server: Apache/2.2.14 (Unix) mod_ssl/2.2.14 OpenSSL/0.9.7a mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
    X-Powered-By: PHP/5.2.12
    Expires: Thu, 19 Nov 1981 08:52:00 GMT
    Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
    Pragma: no-cache
    Set-Cookie: PHPSESSID=ce39b051a9cd493cbe4a86056e11d61f; path=/
    Vary: Accept-Encoding
    Content-Type: text/html


`curl --head --compressed http://site`

    HTTP/1.1 200 OK
    Date: Wed, 08 Feb 2012 08:48:19 GMT
    Server: Apache/2.2.14 (Unix) mod_ssl/2.2.14 OpenSSL/0.9.7a mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
    X-Powered-By: PHP/5.2.12
    Expires: Thu, 19 Nov 1981 08:52:00 GMT
    Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
    Pragma: no-cache
    Set-Cookie: PHPSESSID=513b8ac5818fd043471c8aac44355898; path=/
    Vary: Accept-Encoding
    Content-Encoding: gzip
    Content-Length: 20
    Content-Type: text/html



How to use curl to compare the size of the page with deflate enabled and without using it

Is there any way to find a size of an array?

For Example,

    CREATE TABLE example (id integer[]) ;
    
    INSERT INTO example VALUES ( &#39;{}&#39;);
    
    INSERT INTO example VALUES ( &#39;{5,6,7}&#39;);

From this, is there any possibilities to get a result like following,


    size
    
    0
    
    3


How to find the size of an array in postgresql

I have a small table and a certain field contains the type &quot;**character varying**&quot;. I&#39;m trying to change it to &quot;**Integer**&quot; but it gives an error that casting is not possible.

Is there a way around this or should I just create another table and bring the records into it using a query.

The field contains only integer values.

Content Type	Original Author	Original Content on Stackoverflow
Question	Guapo	View Question on Stackoverflow
Solution 1 - Mysql	socha23	View Answer on Stackoverflow
Solution 2 - Mysql	paxdiablo	View Answer on Stackoverflow
Solution 3 - Mysql	Mithun Sasidharan	View Answer on Stackoverflow
Solution 4 - Mysql	Jukka Dahlbom	View Answer on Stackoverflow
Solution 5 - Mysql	noobie-php	View Answer on Stackoverflow
Solution 6 - Mysql	ajreal	View Answer on Stackoverflow

Acceptable field type and size for email address?

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

Solution 3 - Mysql

Solution 4 - Mysql

Solution 5 - Mysql

Solution 6 - Mysql

How to create an email form that can send email using html

Where to define callback for Task based asynchronous method

Attributions