Question

I have an application where two column could be populated from a number of different applications; one, the XY location (stgeometry) is determined by the application: two, the XY location is typed by the user into separate x and y columns.

I’ve come up with the following trigger to populate the X and Y column in scenario one, and to populate the shape column in scenario 2. It seems to be looping and not populating either column. Where did I go wrong?

    ALTER trigger [dbo].[update_location_geometry]
    --Trigger to allow non-gis input of XY data in X_Coord and Y_Coord columns, yet still populate the WKB
    --shape column with coordinate using 26917 EPSG so that new location will be available to the gis without
    -- additional user intervention
    on [dbo].[TBL_LOCATIONS]
    instead of insert as
    begin
--this block populates stgeometry.shape col with user-input XY and is not using the application to
-- determine xy
    if exists (select top 1 * from inserted where shape is not null)

    update dbo.tbl_locations
    set SHAPE=Geometry::STPointFromText('POINT(' + CAST(X_Coord AS VARCHAR(20)) + ' ' + 
                        CAST(Y_Coord AS VARCHAR(20)) + ')', 26917)
    WHERE (UPDATE(X_Coord) OR UPDATE(Y_Coord))
                 AND objectId IN (SELECT ins.objectId FROM inserted ins) 


  --this block populates the XY column from stgeometry.shape when the application calculated XY   
    update dbo.tbl_locations
    set X_Coord = SHAPE.STX,Y_Coord = SHAPE.STY 
    WHERE (UPDATE(Shape))
                 AND objectId IN (SELECT ins.objectId FROM inserted ins)
    End

Tried this as well, still looping:

  ALTER trigger [dbo].[update_location_geometry]
    --Trigger to allow non-gis input of XY data in X_Coord and Y_Coord columns, yet still populate the WKB
    --shape column with coordinate using 26917 EPSG so that new location will be available to the gis without
    -- additional user intervention
    on [dbo].[TBL_LOCATIONS]
    instead of insert as -- Aaron changed update to insert here


IF UPDATE(X_Coord) OR UPDATE(Y_Coord)

Begin
update dbo.tbl_locations
set SHAPE=Geometry::STPointFromText('POINT(' + CAST(X_Coord AS VARCHAR(20)) + ' ' + 
CAST(Y_Coord AS VARCHAR(20)) + ')', 26917)

END
IF UPDATE(Shape) 
Begin
update dbo.tbl_locations
set X_Coord = SHAPE.STX,Y_Coord = SHAPE.STY 

End

And this produces syntax error:

instead of update as

IF update (X_Coord) OR UPDATE(Y_Coord) AND objectId IN (SELECT ins.objectId FROM inserted ins)

Begin
update dbo.tbl_locations
set SHAPE=Geometry::STPointFromText('POINT(' + CAST(X_Coord AS VARCHAR(20)) + ' ' + 
CAST(Y_Coord AS VARCHAR(20)) + ')', 26917)

END
IF UPDATE(Shape)AND objectId IN (SELECT ins.objectId FROM inserted ins)
Begin
update dbo.tbl_locations
set X_Coord = SHAPE.STX,Y_Coord = SHAPE.STY 

End


Msg 207, Level 16, State 1, Procedure update_location_geometry, Line 10
Invalid column name 'objectId'.
Msg 207, Level 16, State 1, Procedure update_location_geometry, Line 18
Invalid column name 'objectId'.

Final Solution:

ALTER TRIGGER [dbo].[update_location_geometry] ON [dbo].[TBL_LOCATIONS] 
INSTEAD OF INSERT 
AS BEGIN     
IF EXISTS (SELECT 1 FROM inserted WHERE SHAPE IS NOT NULL)     
BEGIN         
INSERT dbo.TBL_Locations(SHAPE, X_Coord, Y_Coord,objectid, loc_name)             
SELECT SHAPE, X_Coord = SHAPE.STX,Y_Coord = SHAPE.STY,objectid, loc_name            
FROM inserted;     
END     
ELSE     
BEGIN         
INSERT dbo.TBL_Locations(SHAPE, X_Coord, Y_Coord,objectid,loc_name)             
SELECT SHAPE=Geometry::STPointFromText('POINT('
+ CAST(X_Coord AS VARCHAR(20)) + ' ' 
+ CAST(Y_Coord AS VARCHAR(20)) + ')', 26917),
X_Coord, Y_Coord,objectid,loc_name
FROM inserted;
END
END

Example of insert:

INSERT INTO [ATBI].[dbo].[TBL_LOCATIONS]
           ([OBJECTID]
           ,[X_Coord]
           ,[Y_Coord]
           ,Loc_Name,
           Notes)

     VALUES
           (368
           ,324999.997
           ,3970798.079
           ,'blahblah'
           ,'notes of test')

Production table:

CREATE TABLE [dbo].[TBL_LOCATIONS](
    [OBJECTID] [int] NOT NULL,
    [FCategory] [nvarchar](16) NULL,
    [MapMethod] [nvarchar](4) NULL,
    [HError] [nvarchar](50) NULL,
    [MapSource] [nvarchar](255) NULL,
    [SourceDate] [datetime2](7) NULL,
    [EditDate] [datetime2](7) NULL,
    [Notes] [nvarchar](255) NULL,
    [Site_ID] [uniqueidentifier] NULL,
    [Meta_MID] [nvarchar](50) NULL,
    [X_Coord] [numeric](38, 8) NULL,
    [Y_Coord] [numeric](38, 8) NULL,
    [Coord_Units] [nvarchar](50) NULL,
    [Coord_System] [nvarchar](50) NULL,
    [UTM_Zone] [nvarchar](50) NULL,
    [Accuracy_Notes] [nvarchar](max) NULL,
    [Unit_Code] [nvarchar](12) NULL,
    [Loc_Name] [nvarchar](100) NULL,
    [Loc_Type] [nvarchar](25) NULL,
    [Updated_Date] [nvarchar](50) NULL,
    [Loc_Notes] [nvarchar](max) NULL,
    [Datum] [nvarchar](5) NULL,
    [Watershed] [nvarchar](50) NULL,
    [StreamName] [nvarchar](50) NULL,
    [NHDReachCode] [nvarchar](14) NULL,
    [TOPO_NAME] [nvarchar](50) NULL,
    [Trail] [nvarchar](100) NULL,
    [Road] [nvarchar](50) NULL,
    [Elevation] [numeric](38, 8) NULL,
    [LAT] [numeric](38, 8) NULL,
    [LON] [numeric](38, 8) NULL,
    [Year_] [nvarchar](4) NULL,
    [County] [nvarchar](30) NULL,
    [State] [nvarchar](30) NULL,
    [IsExtant] [nvarchar](3) NULL,
    [IsSenstive] [nvarchar](3) NULL,
    [Eco_Notes] [nvarchar](50) NULL,
    [EcoGroup] [nvarchar](50) NULL,
    [ELCode] [smallint] NULL,
    [Validation] [nvarchar](50) NULL,
    [LocationDescription] [nvarchar](max) NULL,
    [LocationDirections] [nvarchar](max) NULL,
    [VerbatimLocation] [nvarchar](255) NULL,
    [PlaceName] [nvarchar](75) NULL,
    [SHAPE] [geometry] NULL,
    [Location_ID] [uniqueidentifier] NOT NULL,
 CONSTRAINT [PK_TBL_LOCATIONS] PRIMARY KEY CLUSTERED 
(
    [OBJECTID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[TBL_LOCATIONS]  WITH CHECK ADD  CONSTRAINT [g2_ck] CHECK  (([SHAPE].[STSrid]=(26917)))
GO

ALTER TABLE [dbo].[TBL_LOCATIONS] CHECK CONSTRAINT [g2_ck]
GO

ALTER TABLE [dbo].[TBL_LOCATIONS] ADD  CONSTRAINT [DF__TBL_LOCAT__Globa__12C8C788]  DEFAULT (newsequentialid()) FOR [Location_ID]
GO

Answer 1

In an insert trigger, does checking UPDATE make sense? Did you mean to make it an INSTEAD OF UPDATE trigger instead of INSTEAD OF INSERT?

Also, assuming it should be an UPDATE trigger, I would usually check this way as opposed to the WHERE clause:

IF UPDATE(X_Coord) OR UPDATE(Y_Coord)
BEGIN
    -- first update without first where clause
END

IF UPDATE(Shape)
BEGIN
    -- second update without first where clause
END

Ok so I was stuck on the fact that you were trying to use an instead of insert trigger for an update. The problem is that an instead of trigger requires you to still perform the insert operation yourself, because the trigger is running instead of the insert. Try this (note that if there are other columns being inserted along with SHAPE or X_Coord/Y_Coord, you’ll need to pull those from inserted as well):

CREATE TRIGGER [dbo].[update_location_geometry]
ON [dbo].[TBL_LOCATIONS]
INSTEAD OF INSERT
AS
BEGIN
    INSERT dbo.TBL_Locations(ObjectID, SHAPE, X_Coord, Y_Coord)
        SELECT ObjectID, SHAPE, X_Coord = SHAPE.STX, Y_Coord = SHAPE.STY 
        FROM inserted WHERE SHAPE IS NOT NULL;

    INSERT dbo.TBL_Locations(ObjectID, SHAPE, X_Coord, Y_Coord)
        SELECT ObjectID, SHAPE=Geometry::STPointFromText('POINT(' 
          + CAST(X_Coord AS VARCHAR(20)) + ' ' 
          + CAST(Y_Coord AS VARCHAR(20)) + ')', 26917), 
          X_Coord, Y_Coord 
        FROM inserted WHERE SHAPE IS NULL;
END
GO

I tried this with the following INSERT statements and they populated the table just fine:

INSERT dbo.TBL_Locations(ObjectID, X_Coord, Y_Coord) 
    SELECT 1, 20, 30;

INSERT dbo.TBL_Locations(ObjectID, Shape) 
    SELECT 2, 0x25690000010C00000000000034400000000000003E30;