I have doubt in allocation of bytes ,
For example there is one BIGINT column having 2 values 1,10000.My doubt is for both the values terdata assign 8 bytes(as BIGINT occupies 8 bytes) or it will assign based on number of digits in the value.
There is no doubt - 8 bytes
from the manuals - SQL Data Types and Literals
"BIGINT values are stored as eight bytes with the least significant byte first."
The NUMBER data type is the only variable-length numeric data type.
All the other numeric types are fixed size: BYTEINT, SMALLINT, INTEGER, BIGINT, DECIMAL, and FLOAT.