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EclipseLink and Nullable Parts composite key [message #1700871]

Tue, 07 July 2015 18:48

Christian Dietrich

Messages: 14669
Registered: July 2009

Senior Member

I Have the Following Database Table

Some_Table
----------------
ID_A INT
ID_B INT
ID_C STRING
VALUE STRING

(ID_A,ID_B and ID_C) together for the composite key.
but it may be that ID_A or ID_B is null

i try to solve this as follows

@Entity
@Table(name="Some_Table")
public class SomeTable {

@Column(name="VALUE")
private String value;

@EmbeddedId
private MyKey id;
}

public class MyKey {

@Column(name="ID_C", insertable=false, updatable=false) //cause actually
private String idC;

@Column(name="ID_A", insertable=false, updatable=false)
private BigDecimal idA;

@Column(name="ID_B", insertable=false, updatable=false)
private BigDecimal idB;
}

but that is not working:

during the execution of the query was detected to be null. Primary keys must not contain null.

i even tried to add a @Convert(converter=KeyConverter.class) AttributeConverter
but that doesn work either since the converter is never called an so i cannot return a dummy BigDecimal if DB value is Null

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: EclipseLink and Nullable Parts composite key [message #1701197 is a reply to message #1700871]

Thu, 09 July 2015 19:06

Jan Horyna

Messages: 3
Registered: June 2015

Junior Member

Hi,
I had the same problem some weeks ago.
The true is no part of the compound key can contain nulls.

Workaround: We created new column (Varchar) as new id column and stringified all the values of the old compound key, i.e. 'Val1nullVal2null'.
This way we alway had a valid id.

Have fun
Jan

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