To deal with multiple rasters loaded to a table in a database (can be PostGIS or Oracle, example is Oracle), you can use a TILEINDEX in MapServer.

Database TILEINDEXes are a little odd in MapServer, they require 2 separate layers, a TILEINDEX layer and a RASTER layer that refers to the TILEINDEX layer.

In Oracle, you'll want to create the TILEINDEX as a view to the GEORASTER table of interest.

create or replace view my_raster_tindex as select some_attribute, 'geor: user/pass@tns, raster_table_DATA,'||r.raster.rasterid location, R.RASTER.spatialextent shape from rasters_table r;

This view will then be used for the TILEINDEX layer

LAYER
  name raster_tindex
  TYPE polygon
  PROJECTION
    "init=epsg:xxxx"
  END
  CONNECTIONTYPE ORACLESPATIAL
  CONNECTION user/pass@tns'
  DATA "shape from my_raster_tindex using srid xxxx"
END

Then you add a second layer that is the actual RASTER layer

LAYER
  name db_raster_layer
  TYPE RASTER
  PROJECTION
    "init=epsg:xxxx"
  END
  TILEINDEX "raster_tindex"   #THIS NAME MUST MATCH THE TILEINDEX LAYER NAME
  TILEITEM "location"   #not actually needed if column is named location
  STATUS OFF
  OFFSITE 0 0 0
END

One last piece that is needed is to set the SHAPEPATH to null so that the paths to the raster files are treated as database connections and not files.

Add

SHAPEPATH ""