@Override
  public void setTypeName(String typeName) {
    // type name should already be set by subclass
    return;
  }
Utility method to build the fully qualified data type. For example:
(char,16) becomes char(16).

@param typeName The name of the data type (char or varchar)
@param length The maximum length of the data type
@return A fully qualified field name
serde/src/java/org/apache/hadoop/hive/serde2/typeinfo/BaseCharTypeInfo.java