AddOverviewConstraints — Tag a raster column as being an overview of another.
boolean AddOverviewConstraints(name ovschema, name ovtable, name ovcolumn, name refschema, name reftable, name refcolumn, int ovfactor);
boolean AddOverviewConstraints(name ovtable, name ovcolumn, name reftable, name refcolumn, int ovfactor);
Adds constraints on a raster column that are used to display information in the raster_overviews raster catalog.
The ovfactor parameter represents the scale multiplier in the overview column: higher overview factors have lower resolution.
When the ovschema and refschema parameters are omitted, the first table found scanning the search_path will be used.
Disponibilidad: 2.0.0
CREATE TABLE res1 AS SELECT
ST_AddBand(
ST_MakeEmptyRaster(1000, 1000, 0, 0, 2),
1, '8BSI'::text, -129, NULL
) r1;
CREATE TABLE res2 AS SELECT
ST_AddBand(
ST_MakeEmptyRaster(500, 500, 0, 0, 4),
1, '8BSI'::text, -129, NULL
) r2;
SELECT AddOverviewConstraints('res2', 'r2', 'res1', 'r1', 2);
-- verify if registered correctly in the raster_overviews view --
SELECT o_table_name ot, o_raster_column oc,
r_table_name rt, r_raster_column rc,
overview_factor f
FROM raster_overviews WHERE o_table_name = 'res2';
ot | oc | rt | rc | f
------+----+------+----+---
res2 | r2 | res1 | r1 | 2
(1 row)