code: func PgUserMappingByOid(db XODB, oid pgtypes.Oid) (*PgUserMapping, error) {
  	var err error
  
  	// sql query
  	const sqlstr = `SELECT ` +
  		`tableoid, cmax, xmax, cmin, xmin, oid, ctid, umuser, umserver, umoptions ` +
  		`FROM pg_catalog.pg_user_mapping ` +
  		`WHERE oid = $1`
  
  	// run query
  	XOLog(sqlstr, oid)
  	pum := PgUserMapping{}
  
  	err = db.QueryRow(sqlstr, oid).Scan(&pum.Tableoid, &pum.Cmax, &pum.Xmax, &pum.Cmin, &pum.Xmin, &pum.Oid, &pum.Ctid, &pum.Umuser, &pum.Umserver, &pum.Umoptions)
  	if err != nil {
  		return nil, err
  	}
  
  	return &pum, nil
  }
docs: // PgUserMappingByOid retrieves a row from 'pg_catalog.pg_user_mapping' as a PgUserMapping.
  //
  // Generated from index 'pg_user_mapping_oid_index'.