docs: function addMeta(params, config, conn) {
  
    params = params || {}
  
    // validate
    if (!params.uri || params.uri === '') {
      return 'You must enter a valid uri'
    }
  
    // defaults
    config = config || require('../config/config.js')
  
    debug(params)
  
    // main
    // main
    return new Promise((resolve, reject) => {
  
      if (!conn) {
        var conn = wc_db.getConnection(config.db)
      }
  
      if (!params.subtitlesURI) {
        params.subtitlesURI = null
      }
  
      if (!params.charenc) {
        params.charenc = null
      }
  
      var sql = 'INSERT into Meta select a.id, :length, :subtitlesURI, :charenc from Media a where a.uri = :uri ;'
      debug('addMeta', sql, params)
  
      conn.query(sql, { replacements: { "length" : params.length, "subtitlesURI": params.subtitlesURI, "uri" : params.uri, "charenc" : params.charenc } }).then(function(ret){
        return resolve({"ret" : ret, "conn" : conn})
      }).catch(function(err) {
        return reject({"err" : err, "conn" : conn})
      })
  
    })
  
  }