2022.02.28 修复非空间表的获取info问题

@@ -34,10 +34,11 @@ class Api(ApiTemplate):
 
                 srid_sql = '''select st_srid({}) from public."{}" limit 1'''.format(layer.GetGeometryColumn(),layer.GetName())
                 srid_layer:Layer = pg_ds.ExecuteSQL(srid_sql)
-                srid_feature : Feature = srid_layer.GetNextFeature()
-                if srid_feature:
-                    if srid_feature.GetField(0):
-                        append_dict["srid"] = str(srid_feature.GetField(0))
+                if srid_layer:
+                    srid_feature : Feature = srid_layer.GetNextFeature()
+                    if srid_feature:
+                        if srid_feature.GetField(0):
+                            append_dict["srid"] = str(srid_feature.GetField(0))
 
             else:
                 append_dict["exist"]=0