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From zhangguop...@gmail.com
Subject Is there any logic behind single-valued constraint in ejb-ql?
Date Tue, 11 Dec 2007 09:43:54 GMT
Hi,

I saw in javaranch's discussion group, people summarize about using
single-valued cmr filed in ejb-ql:

"You cannot have a collection-valued CMR field as the SELECT return
type using the dot navigation operator, but you can have CMP fields
and single-valued CMR fields. For collection-valued CMR fields, you
must use range variables with the IN operator in the FROM clause"

I just wonder why ejb-ql specification force these rules. Is there
some logic behind that? For example, these rules make parsing ejb-ql
easier?

Thanks,

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