title: RMySQL dbWriteTable with field.types
body: <p>I have a data frame, called <code>df</code>, that looks like this:</p>
  
  <pre><code>dte, val
  2012-01-01, 23.2323
  2012-01-02, 34.343
  </code></pre>
  
  <p>The type on the columns is date and numeric.  I would like to write this to a MySQL database using an already open connection. The connection works fine as I am able to query the db fine. I try to run the following:</p>
  
  <pre><code>dbWriteTable(con, name="table_name", value=df, field.types=list("date", "double(20,10)"))
  </code></pre>
  
  <p>This generates the error:</p>
  
  <blockquote>
    <p>Error in function (classes, fdef, mtable)  : unable to find an inherited method for function "make.db.names", for signature "MySQLConnection", "NULL"</p>
  </blockquote>
  
  <p>If I do not specify a field.types, and run:</p>
  
  <pre><code>dbWriteTable(con, name="table_name", value=df)
  </code></pre>
  
  <p>I get the error:</p>
  
  <blockquote>
    <p>Error in mysqlExecStatement(conn, statement, ...) : RS-DBI driver: (could not run statement: BLOB/TEXT column 'dte' used in key specification without a key length)</p>
  </blockquote>
  
  <p>Can anyone shed some light on this?</p>
  
  <p>Thanks</p>