Eclipse Community Forums: EclipseLink » Reusing a column across subclasses in eclipselink single table inheritance

Help

Home

Home » Eclipse Projects » EclipseLink » Reusing a column across subclasses in eclipselink single table inheritance

Show: Today's Messages :: Show Polls :: Message Navigator

Reusing a column across subclasses in eclipselink single table inheritance [message #1699275]

Tue, 23 June 2015 08:18

MANISHA SHARMA

Messages: 1
Registered: September 2014

Junior Member

Hi,

In a simple inheritance tree, there are only two subclass entities.

The subclasses both store a key-value pair, but one will be holding a type Encrypted String, and the other one a plain old String.

Now, my question is can I do this:

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
public abstract Attribute {
   @Id
   private Integer id;

   @Column(name="attribute_key")
   private String key;
}

@Entity
public EncryptedAttribute extends Attribute {
   @Column(name="attribute_value")
   private EncryptedString encryptedValue;
}

@Entity
public UnEncryptedAttribute extends Attribute {
   @Column(name="attribute_value")
   private String plainValue;  
}

The Encrypted String and plain String should both end up as varchars in the db, but can I store persistent attributes associated with different sub-classes in the same column? This would avoid the side-effect of storing null values in columns which aren't used in a particular row.

Report message to a moderator

Re: Reusing a column across subclasses in eclipselink single table inheritance [message #1699498 is a reply to message #1699275]

Wed, 24 June 2015 15:14

Chris Delahunt

Messages: 1389
Registered: July 2009

Senior Member

This should work as long as the mapping would use the same database field type. Also remember that you may have difficulty querying on the field - this shouldn't be a problem for EclipseLink generated queries, as it will filter on the type, but might if you are using native queries.

Report message to a moderator

Previous Topic:	Using XMLType in Oracle XE-Database with Eclipselink
Next Topic:	@OneToMany does not work with schema-generation = drop-and-create

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Thu Apr 25 07:35:56 GMT 2024

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter