Re: Nested table-queries

[Jurgis Pralgauskis]

I had some simiar sounding issues + some solution 

https://groups.google.com/forum/?fromgroups=#!topic/web2py/fmyLPCsaoIo

but now I don't have time to examine your problem...

2013 m. balandis 14 d., sekmadienis 19:47:46 UTC+3, D. rašė:

Dear Community,

I just started with web2py and ran into some difficulties:

I would like to display a custom table with my data. For the value of a specific field in each row I need the corresponding information from another table.

This is what I have so far:

def get_extended_info_for_case(case_id):

    # DB-Query here to get the fields&values I need    
    return extended_info

def manage():

    ext_info = lambda row: get_extended_info_for_case(row.cases.id)

    db.cases.extended_info = Field.Virtual(ext_info)

    rows = db(db.cases).select()

    headers = ["ID", "A", "B", "C", "Extended Info"]

    fields = ["id", "a", "b", "c", "extended_info"]

    table = TABLE(THEAD(TR(*[B(header) for header in headers])),

                  TBODY(*[TR(*[TD(row[field]) for field in fields])

                        for row in rows]))

This works when the helper-function get_extended_info returns just a plain string. However, if I have it return a list of tuples that I can then use to dynamically create links within the virtualfield - one for each tuple - I'm lost.

For example: 

extended_info = [(1,"A1"), (223,"whatever")]

resulting entry in the corresponding virtualfield should be a concatenation of several links:

A(A1, _href=URL("edit", args=1)), A(whatever, _href=URL("edit", args=223))

How can I accomplish this? Can I integrate the query to the second databasetable into the first one? Or do I need nested lambdas? I have to admit that I don't fully understand the way lambdas and the nested table-construction work. Is there a way to display this in a more human-readable form? Or am I better of contructing my table in the view instead?

Thanks a lot.

Best regards,

Dan

[D.]

I figured it out myself :-)

I just needed an inline-loop in my lambda-function:

ext_info = lambda row: [A(op, _href=URL("edit", args=op_id, user_signature=True)) + " "  for op, op_id in get_extended_info_for_case(row.cases.id)]

I find this very ugly though (lambdas and inline-loops in general) and it does not look pythonic. Is there any way to make it prettier?

[Jurgis Pralgauskis]

I think you can have the same without lambda

 

def ext_info (row): 

   return [A(op, _href=URL("edit", args=op_id, user_signature=True)) + " "  for op, op_id in get_extended_info_for_case(row.cases.id)]

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Jurgis Pralgauskis
tel: 8-616 77613;
Don't worry, be happy and make things better ;)
http://galvosukykla.lt