Populate_Geometry_Columns

Description

Ensures geometry columns have appropriate type modifiers or spatial constraints to ensure they are registered correctly in the geometry_columns view. By default will convert all geometry columns with no type modifier to ones with type modifiers.

For backwards compatibility and for spatial needs such as table inheritance where each child table may have different geometry type, the old check constraint behavior is still supported. If you need the old behavior, you need to pass in the new optional argument as false use_typmod=false . When this is done geometry columns will be created with no type modifiers but will have 3 constraints defined. In particular, this means that every geometry column belonging to a table has at least three constraints:

If a table oid is provided, this function tries to determine the srid, dimension, and geometry type of all geometry columns in the table, adding constraints as necessary. If successful, an appropriate row is inserted into the geometry_columns table, otherwise, the exception is caught and an error notice is raised describing the problem.

If the oid of a view is provided, as with a table oid, this function tries to determine the srid, dimension, and type of all the geometries in the view, inserting appropriate entries into the geometry_columns table, but nothing is done to enforce constraints.

The parameterless variant is a simple wrapper for the parameterized variant that first truncates and repopulates the geometry_columns table for every spatial table and view in the database, adding spatial constraints to tables where appropriate. It returns a summary of the number of geometry columns detected in the database and the number that were inserted into the geometry_columns table. The parameterized version simply returns the number of rows inserted into the geometry_columns table.

Availability: 1.4.0

Changed: 2.0.0 By default, now uses type modifiers instead of check constraints to constrain geometry types. You can still use check constraint behavior instead by using the new use_typmod and setting it to false.

Enhanced: 2.0.0 use_typmod optional argument was introduced that allows controlling if columns are created with typmodifiers or with check constraints.

Examples

CREATE TABLE public.myspatial_table(gid serial, geom geometry);
INSERT INTO myspatial_table(geom) VALUES(ST_GeomFromText('LINESTRING(1 2, 3 4)',4326) );
-- This will now use typ modifiers.  For this to work, there must exist data
SELECT Populate_Geometry_Columns('public.myspatial_table'::regclass);

populate_geometry_columns
--------------------------
                        1


\d myspatial_table

                                   Table "public.myspatial_table"
 Column |           Type            |                           Modifiers
--------+---------------------------+---------------------------------------------------------------
 gid    | integer                   | not null default nextval('myspatial_table_gid_seq'::regclass)
 geom   | geometry(LineString,4326) |

-- This will change the geometry columns to use constraints if they are not typmod or have constraints already.
--For this to work, there must exist data
CREATE TABLE public.myspatial_table_cs(gid serial, geom geometry);
INSERT INTO myspatial_table_cs(geom) VALUES(ST_GeomFromText('LINESTRING(1 2, 3 4)',4326) );
SELECT Populate_Geometry_Columns('public.myspatial_table_cs'::regclass, false);
populate_geometry_columns
--------------------------
                        1
\d myspatial_table_cs

                          Table "public.myspatial_table_cs"
 Column |   Type   |                            Modifiers
--------+----------+------------------------------------------------------------------
 gid    | integer  | not null default nextval('myspatial_table_cs_gid_seq'::regclass)
 geom   | geometry |
Check constraints:
    "enforce_dims_geom" CHECK (st_ndims(geom) = 2)
    "enforce_geotype_geom" CHECK (geometrytype(geom) = 'LINESTRING'::text OR geom IS NULL)
    "enforce_srid_geom" CHECK (st_srid(geom) = 4326)