VODataService becoming WD, then PR
paul.harrison at manchester.ac.uk
Tue Nov 18 03:49:38 PST 2008
On 2008-11 -18, at 10:06, Gerard wrote:
> A TAP inspired example could be the Database<-Schema<-Table<-Column
> relations in the TAP_SCHEMA,
> ff this were modeled as follows
> primary key(name)
> primary key(database_name, name)
> primary key(database_name, _schema_name, name)
> primary key(database_name, _schema_name, table_name, name)
> Fore xample TAP_SCHEMA.columns has a foreign key (database_name,
> schema_name, table_name) to tables,
> (database_name, schema_name) to schemas and database_name to databases
> This further complicates a column-level definition of the foreign key.
Yes - so I think that my attempt to do this with a single extension
attribute on the TableParam is beginning to stop being "simple". It
would be necessary to have a list value for the fkey.
e.g. on the TAP_SCHEMA.columns.database_name column
and similarly on the other columns that make up the key.
This I think leads us to wanting to go with Gerard's suggestion, which
is effectively a reintroduction of a (better) tableJoin element that
had been previously dropped. I also prefer the idea of having the
ForeignKey defined as a child of Table.
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