Re: 1-to-N (bat) UDF

11 Apr 2015

      Super! I'll give it a try.

Thanks Niels.

On 11 April 2015 at 15:30, Niels Nes  wrote:
...
On Sat, Apr 11, 2015 at 03:24:42PM +0200, Roberto Cornacchia wrote:
...
Hi Niels,
That sounds perfect. I suppose you refer to this: http://
dev.monetdb.org/hg/MonetDB?cmd=changeset;node=5db56a1d5bc5
Do you think I would have any luck trying to port this back to Oct2014?
I checked it in on default as this is more a new feature and not a bug
fix. But it should contain enough to backport it.
Niels
ps we are planning a release too...
...
On 11 April 2015 at 14:06, Niels Nes  wrote:
On Sat, Apr 11, 2015 at 11:03:22AM +0200, Roberto Cornacchia wrote:
    > Hi there,
    >
    > I need a string tokenizer in MonetDB.
    > The problem I have is not with the function itself, but with the
    fact
    > that this is a 1 to N rows function.
    >
    > Implementing this for a single string value is easy enough, using
    a
    > table function that takes a string a returns a table:
    >
    > create function tokenize(s string)
    > returns table (token string)
    > external name tokenize;
    >
    > select *
    > from tokenize("one two three");
    >
    > That's fine.
    > The issue I'm having is with extending this to a column of
    strings.
    >
    > Ideally, given a string column
    >
    > one two three
    > four five six
    > seven eight
    >
    > I'd like to get an output along these lines (simplistic
    representation
    > here):
    >
    > one two three | one
    > one two three | two
    > one two three | three
    > four five six | four
    > four five six | five
    > four five six | six
    > seven eight   | seven
    > seven eight   | eight
    >
    >
    > I can sure code the c function and the mal wrapper to implement
    this,
    > but I can't see how to map it to SQL, given that table functions
    don't
    > accept identifiers as parameters.
    >
    > Any idea? Any possible workaround?
    In default you should be able to call tokenize on a column.
    It will output the 'union' of all per row calls.
    If you would like the 2 column output, you should take care of
    this in your tokenize function, ie return both input and token.
Niels
    > Thanks, Roberto
    >
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--
    Niels Nes, Manager ITF, Centrum Wiskunde & Informatica (CWI)
    Science Park 123, 1098 XG Amsterdam, The Netherlands
    room L3.14,  phone ++31 20 592-4098     sip:4098@sip.cwi.nl
    url: https://www.cwi.nl/people/niels    e-mail: Niels.Nes@cwi.nl
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...
_______________________________________________
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users-list@monetdb.org
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--
Niels Nes, Manager ITF, Centrum Wiskunde & Informatica (CWI)
Science Park 123, 1098 XG Amsterdam, The Netherlands
room L3.14,  phone ++31 20 592-4098     sip:4098@sip.cwi.nl
url: https://www.cwi.nl/people/niels    e-mail: Niels.Nes@cwi.nl
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