On an Oracle DB I have a table with SDO_GEOMETRY objects. I would like to query the database for those polygons with less than x edges. In theory this would be easy with a query like
SELECT * FROM myTable t WHERE LENGTH(t.geometry.sdo_ordinates) < x
Obviously the LENGTH funtion is defined for char and the type of
t.geometry.sdo_ordinates
is oracle.sql.ARRAY so that doesn't work. Shouldn't there be a trivial way to SELECT the length or an array in Oracle? Somehow I'm unable to get the syntax right.
PS: I kind of solved my search with the following query, still the original questerion remains, isn't there an array size/length function?
SELECT * FROM myTable t WHERE LENGTH(t.geomety.Get_WKT()) < (x * c)
No, there is no simple sql function that counts the elements of an array.
However as mentioned here, another idea is a PL/SQL script.
create or replace function get_count(ar in SDO_ORDINATE_ARRAY) return number is
begin
return ar.count;
end get_count;
t.geometry.sdo_ordinates.COUNT
is a PL/SQL attribute that can be used within functions/procedures. Thus that is not a function useable in plain SQL.
Attribute:
value.someAttribute
Function:
doSomething(value)
Clarification: Functions have return values, procedures don't. Source
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