postgis - Problem when calculating longitude and latitude for points

I have a PostGIS database with SRID=900913 (Google Mercator) and I would like to know the latitude and longitude of points.

I use this command:

ST_X(ST_TRANSFORM(the_geom,4283))

Following what is written here, but it doesn't work. I get the error:

ERROR: AddToPROJ4SRSCache: Cannot find SRID (4283) in spatial_ref_sys
SQL state: XX000. 

I tried to add 4283 in the spatial_ref_sys:

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 94283, 'epsg', 4283, '+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs ', 'GEOGCS["GDA94",DATUM["Geocentric_Datum_of_Australia_1994",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6283"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4283"]]');

But I still have the same error.

What does that mean?

Answer

The ST_Transform function takes the output coordinate system as the second parameter - see ST_Transform. The input co-ordinates should already be stored in the GEOMETRY_COLUMNS table / view.

Also, you seem to have the SRID wrong, it is 4326 for standard WGS84 lat/lon.