jpa - Why EclipseLink is adding discriminator column for joined inheritance strategy? -
i using joined inheritance strategy eclipselink jpa implementation. have noticed eclipselink adding discriminator column, named default dtype, database schema. understand, discriminator needed 1 table inheritance strategy, why joined strategy?
eclipselink needs column because i've got errors after removing it. column added performance reasons, etc? not particularly happy since point of view of database schema column unnecessary clutter.
hibernate based jpa not similar.
from joined table inheritance:
in joined table inheritance, each class shares data root table. in addition, each subclass defines own table adds extended state. following example shows 2 tables, project , l_project, 2 classes, project , largeproject:
...
the discriminator column determines type , joined table use need discriminator column in parent table.
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