Re: How to assemble all fields of (any) view into a string?

On 09/07/2016 03:32 PM, Ken Tanzer wrote:
>
>
> On Wed, Sep 7, 2016 at 3:18 PM, Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>> wrote:
>
> On 09/07/2016 01:36 PM, Ken Tanzer wrote:
>
>
>
> On Wed, Sep 7, 2016 at 1:22 PM, Adrian Klaver
> <adrian(dot)klaver(at)aklaver(dot)com <mailto:adrian(dot)klaver(at)aklaver(dot)com>
> <mailto:adrian(dot)klaver(at)aklaver(dot)com
> <mailto:adrian(dot)klaver(at)aklaver(dot)com>>> wrote:
>
> On 09/07/2016 01:15 PM, Ken Tanzer wrote:
>
> Hi. Using version 9.2. I'm trying to create a function
> that
> will take
> a record from any view and assemble it into a string,
> for export to
> another system. For example, this view:
>
> \d ebh_gain
>
> View "public.ebh_gain"
> Column | Type | Modifiers
> -------------------+---------------+-----------
> reporting_unit_id | character(3) |
> case_id | character(10) |
> event_date | character(8) |
> ids_score | character(1) |
> eds_score | character(1) |
> sds_score | character(1) |
> kc_auth_number | integer |
> king_county_id | integer |
>
> would get converted into a string with all the fields
> concatenated
> together, and space-padded to their full lengths.
>
>
> I think an example is needed. I was thinking you wanted the
> field
> values transformed, but the below seems to indicate
> something different.
>
> No transformation is needed, except for padding the fields out
> to their
> maximum lengths. So for example with these values
>
> ('AA','1243','20160801','2','1','1',37,24)
>
> I need a string created that looks like this:
>
> 'AA 1243 201608012113724'
>
> I have a whole bunch of views that I need to do this for, and am
> hoping
> to avoid coding something specific for each one.
>
>
> I can do it relatively easy in plpythonu:
>
> production=# \d str_test
> Table "history.str_test"
> Column | Type | Modifiers
> -------------------+---------------+-----------
> reporting_unit_id | character(3) |
> case_id | character(10) |
> event_date | character(8) |
>
> production=# insert into str_test values ('1', '1234', '09/07/16');
> INSERT 0 1
>
>
> DO
> $$
> rs = plpy.execute("SELECT * FROM str_test", 1)
> cols = rs.colnames()
> plpy.notice(rs.colnames())
> str_out = ""
> for col in cols:
> str_out += str(rs[0][col])
> plpy.notice(str_out)
> $$ LANGUAGE plpythonu;
>
> NOTICE: ['reporting_unit_id', 'case_id', 'event_date']
> CONTEXT: PL/Python anonymous code block
> NOTICE: 1 1234 09/07/16
> CONTEXT: PL/Python anonymous code block
> DO
>
> Yeah, that and a trip to the information schema to pad out the fields
> would get me the string I need. But I was hoping to be able to do this

Well the above has the padding already there, though that assumes
char(x) fields.

> without having the function select the individual record. Ideally:
>
> SELECT my_cat(ebh_gain) FROM ebh_gain;

So do you want one record to be converted at a time or many?

>
> or, at least somewhat more realistically:
>
> SELECT my_cat(ebh_gain,'ebh_gain') FROM ebh_gain;
>
> I know TCL and probably Python and others can work with a record as a
> trigger function. But TCL doesn't seem to accept a record as an
> argument. Can any of the other languages that could also accomplish
> this function? Or some other way? Thanks.
>
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com