2015-01-13 75 views

回答

2
SELECT topology.CreateTopology('topology_name', 1) 
WHERE NOT EXISTS ( 
    SELECT * FROM topology.topology WHERE name = 'topology_name' 
); 

我假設您使用SRID=1自定義了spatial_ref_sys記錄,否則創建語句將無法找到SRID

1

你可以嘗試使用條件表達式和topology.GetTopologyID,如:

SELECT COALESE(topology.GetTopologyID('topology_name'), topology.CreateTopology('topology_name', 1)) AS topo_id;