don't remove layer together with line

model/src/main/java/lcsb/mapviewer/model/graphics/PolylineData.java

@@ -125,7 +125,7 @@ public class PolylineData implements MinervaEntity, Drawable {
   @JsonIgnore
   private long entityVersion;
 
-  @Cascade({CascadeType.ALL})
+  @Cascade({CascadeType.DETACH})
   @ManyToOne(fetch = FetchType.LAZY)
   @JoinTable(
       name = "layer_table_lines",

web/src/test/java/lcsb/mapviewer/web/api/project/map/layer/line/NewLayerLineControllerTest.java

@@ -7,6 +7,7 @@ import lcsb.mapviewer.model.graphics.PolylineData;
 import lcsb.mapviewer.model.map.layout.graphics.Layer;
 import lcsb.mapviewer.persist.dao.graphics.PolylineDataProperty;
 import lcsb.mapviewer.services.interfaces.ILayerLineService;
+import lcsb.mapviewer.services.interfaces.ILayerService;
 import lcsb.mapviewer.services.interfaces.IMinervaJobService;
 import lcsb.mapviewer.services.interfaces.IProjectService;
 import lcsb.mapviewer.web.ControllerIntegrationTest;
@@ -46,6 +47,9 @@ public class NewLayerLineControllerTest extends ControllerIntegrationTest {
   @Autowired
   private ILayerLineService layerLineService;
 
+  @Autowired
+  private ILayerService layerService;
+
   @Autowired
   private IProjectService projectService;
 
@@ -242,6 +246,7 @@ public class NewLayerLineControllerTest extends ControllerIntegrationTest {
         .andExpect(status().isOk());
 
     assertNull(layerLineService.getById(lineId));
+    assertNotNull(layerService.getById(layerId));
   }
 
   @Test