On Dec 16, 2011, at 1:42 PM, Gregg Lind wrote:
> My search skills are failing me, and I hope you all can help.
> (Apologies that there is some heresy here)
>
> Assumptions:
>
> 1) Suppose I have objects made from json (dicts of strings, lists of dicts,
> etc.)
> 2) (for simplicity, assume these nestings don't go very deep)
> 3) getting this right 90% of the time is fine, and it can assume there are
> only 1:1 and 1:many.
>
> Question:
>
> Is there a tool, or what is the easiest way to create / autogenerate a
> sensible schema based on the object?
> I am looking for a function with this sort of signature:
>
>
> obj = {'id':1,
> 'name': 'Gregg',
> 'events': ['ts': 129292939392, 'what': 'keypress'},
> {'ts': 129292939394, 'what': 'click'}]
> }
>
> def gen_schemas_and_create_table_statements(obj=obj, primary_key='id')
>
> that would give something like:
>
> * 2 (or maybe 3) tables: table1: pk id, string name ; table2
> (events): foreign id, ts, what
>
> along with the sql to create them.
It's possible but a little involved since it has to traverse through the whole
structure, build up a tree of all the attribute names it finds, then apply
various geometries to known table structures. Step one would be to organize
a structure like this:
container:root
name:id; type:int
name:name; type: string; length:5 (based on the longest length you see in
the data)
name events; type:collection of event_obj
container:event_obj
name:ts; type:int;
name:what; type:string
then you go through that and generate two tables. the tables would probably
get surrogate primary keys added in, and you can also make a rule "if the
container already has an integer name 'id', that's the pk".
the structure is essentially a tree (every node has one parent) so I don't
think you'd see any many-to-many relationships falling out of it.
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