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

On Wed, Sep 7, 2016 at 3:18 PM, Adrian Klaver <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>> 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 without
having the function select the individual record. Ideally:

SELECT my_cat(ebh_gain) FROM ebh_gain;

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.

>
>