On Sat, 4 Apr 2009, Xiao Yafeng wrote:

3. Could I define primary key for a bag variable?

All items in a Bag are "primary keys", but there's no data additional
data associated with it.

    I mean whether I can see Set as a table  and Bag as a table with a
unique constraint? like:
       subset test of Bag(test_name Str, test_ID Int, primary key(test_ID))

I don't think you can really do something like that. Perl 6 as specified leaves many things up to libraries. Implementing a Table type will no doubt be one of those things. I would like to have a Table type that will work well with the Tree/Plex type that I am working on.

In the meantime, a table would need to be represented as an array of hashes, or a hash of arrays.


| Name: Tim Nelson                 | Because the Creator is,        |
| E-mail: wayl...@wayland.id.au    | I am                           |

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