Lossless Join Property

join relational-database database-normalization natural-join
user559142 picture user559142 · Apr 24, 2011 · Viewed 34.2k times · Source

Can someone please explain to me what is meant by the lossless join property in a relation schema?

Is it the ability to maintain the semantics of information/data during the decomposition of relations whilst normalising?

Answer

user559142 picture user559142 · Apr 25, 2011

@Falcon - you are right - but this is a more substantial definition...

The lossless join property is a feature of decomposition supported by normalisation. It is the ability to ensure that any instance of the original relation can be identified from corresponding instances in the smaller relations.

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