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Degenerate natural realjoin should be Cartesian product #14

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apjanke opened this issue Mar 2, 2019 · 2 comments
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Degenerate natural realjoin should be Cartesian product #14

apjanke opened this issue Mar 2, 2019 · 2 comments
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apjanke commented Mar 2, 2019 •
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Right now, a degenerate realjoin (that is, no variable names in common) produces an error, just like a degenerate join. In relational algebra, a degenerate join (no key columns in common) produces a Cartesian product, not an error. realjoin should probably do that.

The “plain” join should not degenerate to cartesian product, for Matlab compatibility: I'm pretty sure Matlab's table's join requires at least 1 common key column, defined either naturally or by input options.
@apjanke apjanke changed the title Degenerate natural join should be cartesian product Degenerate natural realjoin should be cartesian product Mar 2, 2019
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@apjanke apjanke self-assigned this Mar 2, 2019
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apjanke commented Mar 2, 2019

I've added a cartesian() method so this would be easy to implement now.

@apjanke apjanke changed the title Degenerate natural realjoin should be cartesian product Degenerate natural realjoin should be Cartesian product Mar 2, 2019
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apjanke commented Mar 3, 2019

Done in 022d6c9.

@apjanke apjanke closed this as completed Mar 3, 2019
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