def dispatch(event, table, bind):
if event == 'before-create':
for c in table.c:
# Add spatial indices for the Geometry and Geography columns
if isinstance(c.type, (Geometry, Geography)) and \
c.type.spatial_index is True:
idx_name = 'idx_%s_%s' % (table.name, c.name)
get_or_create_GIST_Index(table, idx_name, c)
if event in ('before-create', 'before-drop'):
# Filter Geometry columns from the table with management=True
# Note: Geography and PostGIS >= 2.0 don't need this
gis_cols = [
c for c in table.c
if isinstance(c.type, Geometry) and c.type.management is True
]
# Find all other columns that are not managed Geometries
regular_cols = [x for x in table.c if x not in gis_cols]
# Save original table column list for later
table.info["_saved_columns"] = table.c
# Temporarily patch a set of columns not including the
# managed Geometry columns
column_collection = expression.ColumnCollection()
for col in regular_cols:
column_collection.add(col)
table.columns = column_collection
if event == 'before-drop':
# Drop the managed Geometry columns with DropGeometryColumn()
table_schema = table.schema or 'public'
for c in gis_cols:
stmt = select([
func.DropGeometryColumn(table_schema, table.name,
c.name)
])
stmt = stmt.execution_options(autocommit=True)
bind.execute(stmt)
elif event == 'after-create':
# Restore original column list including managed Geometry columns
table.columns = table.info.pop('_saved_columns')
table_schema = table.schema or 'public'
for c in table.c:
# Add the managed Geometry columns with AddGeometryColumn()
if isinstance(c.type, Geometry) and c.type.management is True:
stmt = select([
func.AddGeometryColumn(table_schema, table.name,
c.name, c.type.srid,
c.type.geometry_type,
c.type.dimension)
])
stmt = stmt.execution_options(autocommit=True)
bind.execute(stmt)
# Add spatial indices for the Raster columns
#
# Note the use of ST_ConvexHull since most raster operators are
# based on the convex hull of the rasters.
if isinstance(c.type, Raster) and c.type.spatial_index is True:
bind.execute(
'CREATE INDEX "idx_%s_%s" ON "%s"."%s" '
'USING GIST (ST_ConvexHull("%s"))' %
(table.name, c.name, table_schema, table.name, c.name))
elif event == 'after-drop':
# Restore original column list including managed Geometry columns
table.columns = table.info.pop('_saved_columns')
def dispatch(event, table, bind):
if event in ('before-create', 'before-drop'):
# Filter Geometry columns from the table with management=True
# Note: Geography and PostGIS >= 2.0 don't need this
gis_cols = [
c for c in table.c
if isinstance(c.type, Geometry) and c.type.management is True
]
# Find all other columns that are not managed Geometries
regular_cols = [x for x in table.c if x not in gis_cols]
# Save original table column list for later
table.info["_saved_columns"] = table.c
# Temporarily patch a set of columns not including the
# managed Geometry columns
column_collection = expression.ColumnCollection()
for col in regular_cols:
column_collection.add(col)
table.columns = column_collection
if event == 'before-drop':
# Drop the managed Geometry columns
for c in gis_cols:
if bind.dialect.name == 'sqlite':
drop_func = 'DiscardGeometryColumn'
elif bind.dialect.name == 'postgresql':
drop_func = 'DropGeometryColumn'
else:
raise ArgumentError(
'dialect {} is not supported'.format(
bind.dialect.name))
args = [table.schema] if table.schema else []
args.extend([table.name, c.name])
stmt = select([getattr(func, drop_func)(*args)])
stmt = stmt.execution_options(autocommit=True)
bind.execute(stmt)
elif event == 'after-create':
# Restore original column list including managed Geometry columns
table.columns = table.info.pop('_saved_columns')
for c in table.c:
# Add the managed Geometry columns with AddGeometryColumn()
if isinstance(c.type, Geometry) and c.type.management is True:
args = [table.schema] if table.schema else []
args.extend([
table.name, c.name, c.type.srid, c.type.geometry_type,
c.type.dimension
])
if c.type.use_typmod is not None:
args.append(c.type.use_typmod)
stmt = select([func.AddGeometryColumn(*args)])
stmt = stmt.execution_options(autocommit=True)
bind.execute(stmt)
# Add spatial indices for the Geometry and Geography columns
if isinstance(c.type, (Geometry, Geography)) and \
c.type.spatial_index is True:
if bind.dialect.name == 'sqlite':
stmt = select(
[func.CreateSpatialIndex(table.name, c.name)])
stmt = stmt.execution_options(autocommit=True)
bind.execute(stmt)
elif bind.dialect.name == 'postgresql':
if table.schema:
bind.execute(
'CREATE INDEX "idx_%s_%s" ON "%s"."%s" '
'USING GIST ("%s")' %
(table.name, c.name, table.schema, table.name,
c.name))
else:
bind.execute(
'CREATE INDEX "idx_%s_%s" ON "%s" '
'USING GIST ("%s")' %
(table.name, c.name, table.name, c.name))
else:
raise ArgumentError(
'dialect {} is not supported'.format(
bind.dialect.name))
# Add spatial indices for the Raster columns
#
# Note the use of ST_ConvexHull since most raster operators are
# based on the convex hull of the rasters.
if isinstance(c.type, Raster) and c.type.spatial_index is True:
if table.schema:
bind.execute('CREATE INDEX "idx_%s_%s" ON "%s"."%s" '
'USING GIST (ST_ConvexHull("%s"))' %
(table.name, c.name, table.schema,
table.name, c.name))
else:
bind.execute('CREATE INDEX "idx_%s_%s" ON "%s" '
'USING GIST (ST_ConvexHull("%s"))' %
(table.name, c.name, table.name, c.name))
elif event == 'after-drop':
# Restore original column list including managed Geometry columns
table.columns = table.info.pop('_saved_columns')