A test of using BigNum and Floats. Conclusion: when you store a float in the database it seems to be about the same if you are careful about how you use the floats.

BigNum.java

import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
import java.util.Scanner;
import java.lang.Float;

class BigNum {
  public static void main(String[] args) {
    System.out.println("Hi");
    BigDecimal jim = new BigDecimal("3.2");
    BigDecimal billJim = jim.add(new BigDecimal("3.2"));

    System.out.println(String.format("Big Decimal The jim: %.10f", jim));
    System.out.println(String.format("Big Decimal the billJim: %.10f", billJim));

    float fjim = new Float("3.2");
    float fBillJim = fjim + fjim;

    System.out.println(String.format("Float The fjim: %.10f", fjim));
    System.out.println(String.format("Float the fbillJim: %.10f", fBillJim));

    System.out.println("All to float after rounding: ");

    jim.round(new MathContext(2, RoundingMode.HALF_EVEN));
    billJim.round(new MathContext(2, RoundingMode.HALF_EVEN));

    System.out.println(String.format("Big Decimal The jim: %.10f", jim.floatValue()));
    System.out.println(String.format("Big Decimal the billJim: %.10f", billJim.floatValue()));

    float djim = Math.round(fjim * 100) / 100;
    float dbillJim = Math.round(fBillJim * 100) / 100;

    System.out.println(String.format("Float The fjim: %.10f", djim));
    System.out.println(String.format("Float the fbillJim: %.10f", dbillJim));
  }
}

/* 
OUTPUT: 
Hi
Big Decimal The jim: 3.2000000000
Big Decimal the billJim: 6.4000000000
Float The fjim: 3.2000000477
Float the fbillJim: 6.4000000954
All to float after rounding:
Big Decimal The jim: 3.2000000477
Big Decimal the billJim: 6.4000000954
Float The fjim: 3.0000000000
Float the fbillJim: 6.0000000000
*/