No SQLPlus podemos criar uma view que inclui
rownum para ver exatamente qual tipo de dados o Oracle usa:TEST>create view v_test as select rownum rn, dummy from dual;
View created.
TEST>desc v_test
Name Null? Type
-------- -------- -------------
RN NUMBER
DUMMY VARCHAR2(1)
Então, para a Oracle, essa pseudocoluna é um Número. Que com base neste link ( http:// /download.oracle.com/docs/cd/B28359_01/server.111/b28318/datatype.htm#i16209 ) pode segurar:
The following numbers can be stored in a NUMBER column:
-Positive numbers in the range 1 x 10^-130 to 9.99...9 x 10^125 with up to 38 significant digits
-Negative numbers from -1 x 10^-130 to 9.99...99 x 10^125 with up to 38 significant digits
-Zero
-Positive and negative infinity (generated only by importing from an Oracle Database, Version 5)
