code: func (t *TableMap) ColMap(field string) *ColumnMap {
  	for _, col := range t.Columns {
  		if col.fieldName == field || col.ColumnName == field {
  			return col
  		}
  	}
  	panic(fmt.Sprintf("No ColumnMap in table %s type %s with field %s",
  		t.TableName, t.gotype.Name(), field))
  }
docs: // ColMap returns the ColumnMap pointer matching the given struct field
  // name.  It panics if the struct does not contain a field matching this
  // name.