<div>
Yes possible..<br />
<br />
SQL Solution , try<br />
<br />
SELECT CONCAT( 'h' , RIGHT(RAND(),5) )
</div>


<div>
One more option for &lt;&nbsp;SQL Server 2012<br />
<br />
SELECT 'h' + CAST(CONVERT(NUMERIC(12,0)<wbr />,RAND() * 99999) + 10000 AS VARCHAR(7))
</div>


<div>
By Unique constraint to the column, you can achieve this.
</div>


<div>
Since you have to generate next ID in a custom format, better go for sequence approach to make sure no duplicates. <br />
Try any of the explained approach here<br />
<a href="http://www.sqlteam.com/article/custom-auto-generated-sequences-with-sql-server" rel="ugc">http://www.sqlteam.com/article/custom-auto-generated-sequences-with-sql-server</a>
</div>


<div>
Yes you can also create unique constraints..Approach below.<br />
<br />
<b>DataTable at ;<br />
<br />
UniqueConstraint aUnique = &nbsp;new UniqueConstraint(<br />
new DataColumn[] { at.Columns[&quot;ID&quot;], at.Columns[&quot;Name&quot;] });<br />
<br />
at.Constraints.Add(aUnique<wbr />);</b>
</div>


<div>
<blockquote>
the 5 numbers can be random, but once it is created, it can't be duplicated.
</blockquote>
Choose one of the above solutions to implement the generation of the values but to assure that's no duplicates you'll need to create an unique index on the field: <br />

<pre><code class="code-1 nolinks" id="code-20-41829376-1"><span>CREATE UNIQUE INDEX IndexName ON TableName (ColName)</span>
</code></pre>
<br />
or create a Primary Key if you don't have one in the table:<br />

<pre><code class="code-1 nolinks" id="code-20-41829376-2"><span>ALTER TABLE TableName  </span>
<span>ADD CONSTRAINT PK_TableName_ColName PRIMARY KEY (Colname)</span>
</code></pre>
</div>


<div>
This is the best solution. Without using SQL is perfect. Good Job
</div>


<div>
<div class="content wysiwyg-content">
I would like to create unique identifier like below.<br />
<br />
1. h111111<br />
<br />
the format is <br />
1. Must start &quot;h&quot;<br />
2. with 5 numbers only<br />
<br />
the 5 numbers can be random, but once it is created, it can't be duplicated.<br />
<br />
is it possible?
</div>
</div>


I would like to create unique identifier like below.

1. h111111

the format is 
1. Must start "h"
2. with 5 numbers only

the 5 numbers can be random, but once it is created, it can't be duplicated.

is it possible?

C# primary key

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