How to handle numbers bigger than machine representative number?

Question

Assuming now I\'m assigning ID number to my database, the database is huge(items more than machine representative number).

I\'m using Java, I know the biggest data type

Answer 1

Use java.math.BigInteger.

BigInteger a = new BigInteger("123456789012345678901234567890");
BigInteger b = new BigInteger("314159265");
BigInteger c = a.add(b);
System.out.println(c);

Note (1) BigIntegers are immutable and (2) you have to use the methods add, subtract, etc. rather than +, -, etc.

Also, BigInteger (and its floating-point analog, BigDecimal) is much lower slower than primitive types. BigInteger is fine for most cases, but avoid it if possible in performance sensitive code.