function insertPersonData(filename, tableSchema) {
  return getSampleData(filename).then(
      function(data) {
        var rows = data.map(function(obj) {
          obj.dateOfBirth = convertDate(obj.dateOfBirth);
          obj.dateOfDeath = convertDate(obj.dateOfDeath);
          return tableSchema.createRow(obj);
        });
        return db.insert().into(tableSchema).values(rows);
      });
}
Inserts data in the database.
@param {string} filename The name of the file holding JSON data.
@param {!movie.db.schema.Actor|!movie.db.schema.Director} tableSchema The
    schema of the table corresponding to the data.
@return {!IThenable<!lf.query.Insert>}