Hi All,
I'm trying to convert some code I wrote over to using SA. I have code
that generates an HTML given the name of a table, it parses the
information_schema to get the structure of the table, then creates an
SQL query to get the data and formats the table with the column names at
the top and one row per <TR>. The simple part of that I've switched
over to using SA metadata, but now I'm looking to take the next step and
dereference any foreign keys.
Because of how I set up my schema, any table that is referenced via a
foreign key will have a PK column named "id" and a varchar called "name"
that I want to display in place of the FK column in the referencing table.
Will something in SA build this SQL for me? Right now I'm playing with
a loop like this:
def dereferenced_columns( self ):
columnnames = []
derefcolumnstext = ''
for column in self.table.columns:
if column.foreign_key:
# do whatever it takes to figure out the foreign key
# and add it to my list
else:
columnnames.append( "%s" % column )
return derefcolumnstext += ','.join( columnnames )
And I'll end up doing something similar with the table clause to create
deterministic aliases, I can't actually use the table names as they
appear in the "table.foreignkey.column" since some tables have FKs to
themselves and some tables need to be referenced multiple times.
I'm new to SA and unfamiliar with all the functionality, most examples
assume that you're creating the schema and have implicit knowledge of
it, rather than trying to read it from the metadata, so I'm doing a lot
of iteration and dir()'s over columns objects in the metadata and it's
slow going. Anyone see a simplification to what I'm doing? I can't
help feeling like I'm making this harder than it should be.
Thanks,
e.
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