Every so often, on irc, someone asks how to get value from column that is passed as argument.
This is generally seen as not possible, as pl/PgSQL doesn't have support for dynamic column names.
We can work around it, though. Are the workarounds usable, in terms of performance?
Continue reading Getting value from dynamic column in pl/PgSQL triggers?
On 28th of March 2018, Peter Eisentraut committed patch:
Transforms for jsonb to PL/Python Add a new contrib module jsonb_plpython that provide a transform between jsonb and PL/Python. jsonb values are converted to appropriate Python types such as dicts and lists, and vice versa. Author: Anthony Bykov <a.bykov@postgrespro.ru>
and then, on 3rd of April 2018, he also committed patch:
Transforms for jsonb to PL/Perl Add a new contrib module jsonb_plperl that provides a transform between jsonb and PL/Perl. jsonb values are converted to appropriate Perl types such as arrays and hashes, and vice versa. Author: Anthony Bykov <a.bykov@postgrespro.ru>
Continue reading Waiting for PostgreSQL 11 – Transforms for jsonb to PL/Python and to PL/Perl
On 26th of April, Peter Eisentraut committed patch:
Add transforms feature This provides a mechanism for specifying conversions between SQL data types and procedural languages. As examples, there are transforms for hstore and ltree for PL/Perl and PL/Python. reviews by Pavel Stěhule and Andres Freund
On 11th of December, Peter Eisentraut committed patch:
PL/Perl: Add event trigger support From: Dimitri Fontaine <dimitri@2ndQuadrant.fr>
Continue reading Waiting for 9.4 – PL/Perl: Add event trigger support
One of the questions that gets asked quite a lot, is: how can you use variables in your queries? Other databases have them, does PostgreSQL?
Actually the answer is “no". But, it is actually very easy to work around, and what's more important – quite often, what you need are not variables in queries, but rather variables in client. What does it mean? Let's see.
On 18th of February, Alvaro Herrera committed patch:
Convert Postgres arrays to Perl arrays on PL/perl input arguments More generally, arrays are turned in Perl array references, and row and composite types are turned into Perl hash references. This is done recursively, in a way that's natural to every Perl programmer. To avoid a backwards compatibility hit, the string representation of each structure is also available if the function requests it. Authors: Alexey Klyukin and Alex Hunsaker. Some code cleanups by me.
I have a mixed love/hate relationship with tests.
I hate writing them. I hate remembering to add them when I'm in the zone, and application code is flowing freely from the tips of my fingers.
But when I do add them, I absolutely love the ability to twist and replace the most core innards of application, and be able to tell that at least the sanity check of the code passes.
I love them even more when they prevent me for repeating some mistake/bug – i.e. when there is a bug, and I have tests (which clearly failed, as they didn't catch the bug), I add test for this specific bug, so I know that in future it will not happen again.
For a long time I've been fan of stored procedures (or functions) – of course not for everything, but where it makes sense.
Just recently I wrote about DO command in PostgreSQL 8.5, and now (since 29th of November) we have DO with PL/Perl support.
Written by Joshua Tolley and committed by Tom Lane, the patch:
Log Message: ----------- Add support for anonymous code blocks (DO blocks) to PL/Perl. Joshua Tolley, reviewed by Brendan Jurd and Tim Bunce
Having new VARIADIC functions, I decided it would be cool to be able to write sprintf() function.
Basically the idea is simple, plperl function, which takes “format", and list of arguments and returns generated output.
Continue reading Writing sprintf, and overcoming limitations in pl/perl
MySQL has this nifty/annoying feature/bug of special data type “TIMESTAMP". It is like a DATETIME, but it gets automatically updated whenever you modify the row.
I'll try to add the same feature to PostgreSQL.