postgres function based kv storage for sql algorithms.

pg_kv_store_functions.sql

-- -------------------------------------------
-- This is an implementation of a key, value
-- store for function based kv storage for
-- different sql based algorithms to utilize
-- in postgres.
-- -------------------------------------------
-- Author: Cody Kochmann
-- license: MIT
-- -------------------------------------------

CREATE TABLE IF NOT EXISTS _kv(
	k TEXT UNIQUE primary key,
	v TEXT
);

DROP FUNCTION IF EXISTS kv_del;
CREATE FUNCTION kv_del(target_key TEXT) RETURNS BOOLEAN AS $$
BEGIN
	DELETE FROM _kv WHERE k=target_key;
	RETURN true;
END;
$$ language plpgsql;

DROP FUNCTION IF EXISTS kv_set;
CREATE FUNCTION kv_set(target_key TEXT, target_value TEXT) RETURNS VOID AS $$
BEGIN
	INSERT INTO _kv (k, v) VALUES (target_key, target_value) on conflict(k) do update set v=target_value;
END;
$$ language plpgsql;

DROP FUNCTION IF EXISTS kv_get;
CREATE FUNCTION kv_get(target_key TEXT) RETURNS TEXT
AS $$
DECLARE
	out TEXT;
BEGIN
	SELECT v FROM _kv INTO out WHERE k=target_key LIMIT 1;
	RETURN out;
END;
$$ language plpgsql;


-- -------------------------------------------
-- Example code below to show functionality
-- -------------------------------------------
-- SELECT kv_set('waffles', 'please');
-- SELECT kv_get('waffles');
-- SELECT * from _kv;
--
-- SELECT kv_set('waffles', 'yes more');
-- SELECT kv_get('waffles');
-- SELECT * from _kv;
--
-- SELECT kv_del('waffles');
-- SELECT * from _kv;
-- SELECT kv_get('waffles');
-- -------------------------------------------