title: SQL Server String column as a unique key
body: <p>I am using a SQL server table to keep related information with a URL . So there is a Column as "URL" and its type is VARCHAR . In the application we have to use this URL as a unique key to query for information (We are using something like SELECT * FROM Table WHERE URL = "www.google.com\ig")</p>
  
  <p>Is there any disadvantages or known drawbacks in using a URL as a unique key?</p>