Get ST_GEOMETRY object's attribute

[Bud]

I have an SDE.ST_GEOMETRY value (Oracle 18c):

select
    sde.st_geometry('LINESTRING EMPTY', 26917) as shape
from
    dual

I want to select one of the ST_GEOMETRY object's attributes:

• Entity
• Numpts
• Minx, miny, maxx, maxy
• Area
• Len
• SRID
• Points

How can I do that with Oracle SQL? 

[Bud]

1. Use dot notation:

select
    sde.st_geometry('LINESTRING EMPTY', 26917).len as shape
from
    dual

If the shape column wasn't already wrapped in brackets via a function, then we would need to add the brackets:

select
    (shape).len
from
    my_fc

2. Or, use a table alias:

select
    a.shape.len
from
    my_fc a

3. Or, use the TREAT() function:

select
    treat(shape as sde.st_geometry).len
from
    my_fc

Although that might be misguided/unnecessary, since wrapping the column in brackets achieves the same thing (brackets is my preferred technique).

[Bud]

If I understand correctly, SDO_GEOMETRY has similar attributes. Additionally, SDO_GEOMETRY has methods (aka member functions):

• Get_Dims
• Get_GeoJson
• Get_GType
• Get_LRS_Dim
• Get_WKB
• Get_WKT
• ST_CoordDim
• ST_IsValid

Techniques for selecting an object's attribute

Replace value in SDO_ELEM_INFO_ARRAY varray

Modify SDO_ELEM_INFO_ARRAY of existing geometry

[Bud]

For my notes, the result from an object's attribute can be different than the result from the corresponding ST_GEOMETRY function:

Why is (SHAPE).ENTITY different from SDE.ST_ENTITY(SHAPE)?