Re: function

Normunds wrote:
> Hi all,
>
> how can I write function which takes text from one field, replaces
> some characters and puts it in other field? I have array with old and
> new values.
>
> For example:
> old array = {'r', 'Z', 'o'}
> new array = {'s', 'm', 't'}
> old field value = 'Zorro'
> new field value which must calculate this function = 'mtsst'
>
> This function will be used in update trigger.
> Any ideas?

Tcl has a "map" functionality as subcommand of "string". I
think it appeared in version 8.1. To use the example below,
your Tcl installation must be 8.1 or newer when rebuilding
PostgreSQL configured with "--with-tcl" and enable PL/Tcl
with "createlang".

CREATE FUNCTION string_map(text, text) RETURNS text AS '
return [string map $2 $1]
' LANGUAGE 'pltcl';
CREATE
SELECT string_map('Zorro', 'r s Z m o t');
string_map
------------
mtsst
(1 row)

As you see, the old and new arrays are both coded into the
second argument. It is a key, value pair list, with usual Tcl
quoting for lists. Can you convert your arrays to that?

Jan

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