How do I map a BigDecimal in Hibernate so I get back the same scale I put in?

Question

In Java, new BigDecimal("1.0") != new BigDecimal("1.00") i.e., scale matters.

This is apparently not true for Hibernate/SQL Server, however. If I set the scale on a BigDecimal to a particular value, save the BigDecimal to the database via Hibernate and then re-inflate my object, I get back a BigDecimal with a different scale.

For instance, a value of 1.00 is coming back as 1.000000, I assume because we're mapping BigDecimals to a column defined as NUMERIC(19,6). I can't just define the column as the required scale as I need to store both Dollar and Yen values (for example) in the same column. We need to represent the BigDecimals as numeric types in the database for the benefit of external reporting tools.

Does there exist a Hibernate UserType which maps BigDecimal "properly", or do I have to write my own?

score 2 · Answer 1 · edited May 23 '17 at 11:44

2

Just for informational sake, I can tell you that the creation of the BigDecimal coming back from the database is done by the proprietary JDBC driver's implementation of the 'getBigDecimal' method of the database-specific 'ResultSet' sub-class.

I found this out by stepping thru the Hibernate source code with a debugger, while trying to find the answer to my own question.

edited May 23 '17 at 11:44

Community

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answered Feb 07 '14 at 01:36

DuncanKinnear

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score 1 · Answer 2 · answered Jul 01 '11 at 07:52

I think this will work, I didn't test it though.

public class BigDecimalPOJO implements Serializable {

    private static final long serialVersionUID = 8172432157992700183L;

    private final int SCALE = 20;
    private final RoundingMode ROUNDING_MODE = RoundingMode.CEILING;
    private BigDecimal number;

    public BigDecimalPOJO() {

    }

    public BigDecimal getNumber() {
        return number.setScale(SCALE, ROUNDING_MODE);
    }

    public void setNumber(BigDecimal number) {
        this.number = number.setScale(SCALE, ROUNDING_MODE);
    }
}

score -4 · Answer 3 · answered Jul 01 '11 at 06:24

-4

Not sure, but you can check equality using a.compareTo(b) == 0.

answered Jul 01 '11 at 06:24

Steve

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This doesn't really help me--I need the number of decimal places preserved for display purposes. – Robert Atkins Jul 05 '11 at 05:41
1

That's a different problem entirely. You want a consistent way to represent the number as a string. `String.format(String, Object...)` will help you solve that problem. – Steve Jul 05 '11 at 06:03

How do I map a BigDecimal in Hibernate so I get back the same scale I put in?

3 Answers3

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