title: NCHAR(1) vs BIT
body: <p>I'm working under refactoring of database (SQL Server 2008) scheme and gather arguments to change <code>NCHAR(1)</code> columns (which keep <code>Y|N</code> values) to <code>BIT</code>. Everybody understand this is necessary and don't know why does it take place but this change affects production database so weighty arguments are required. Table keeps address catalog (up to 1m of records).</p>
  
  <p>First argument I found - each <a href="http://msdn.microsoft.com/ru-ru/library/ms186939.aspx" rel="nofollow noreferrer">nchar fields</a> take 2 bytes, each 8 <a href="http://msdn.microsoft.com/en-us/library/ms177603.aspx" rel="nofollow noreferrer">bit fields</a> - 1 byte (next 8 - additional 1 byte).</p>
  
  <p>What's next? Maybe some indexes performance issues?</p>