PostgreSQL with R

PostgreSQL with R

http://www.joeconway.com/presentations/plr-PGConfNYC2014.pdf

sudo apt-get install postgresql-9.4-plr

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CREATE EXTENSION plr;

CREATE OR REPLACE FUNCTION r_lib_paths ()
RETURNS text AS '
    .libPaths()  
' LANGUAGE 'plr';
 
SELECT r_lib_paths();

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CREATE OR REPLACE FUNCTION r_version (text)
RETURNS text AS '
    R.Version()
' LANGUAGE 'plr';

SELECT r_version();

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DROP FUNCTION r_apriori(query text);

CREATE OR REPLACE FUNCTION r_apriori(query text) returns TABLE(quantity text, quantity2 float8) AS '
  library("arules") # install as sudo

  df    <- pg.spi.exec(query)
  trans <- as(split(df$product_id, df$transaction_id), "transactions")
  rules <- apriori(trans, parameter = list(minlen=2, maxlen=3, sup = 0.00005, conf = 0.001))
	
  itemsets     <- unique(generatingItemsets(rules))
  itemsets.df  <- as(itemsets, "data.frame")
  itemsets.df$items <- as.character(itemsets.df$items)
  return(itemsets.df)
' LANGUAGE 'plr' STRICT;

SELECT * from r_apriori('
SELECT DISTINCT
  warehouses.product_id,
  user_id AS transaction_id
FROM
  line_items
  INNER JOIN users ON users.id = line_items.user_id
  INNER JOIN warehouses ON warehouses.id = line_items.warehouse_id
  INNER JOIN products ON products.id = warehouses.product_id
AND (products.deleted_at IS NULL)
WHERE
  line_items.deleted_at IS NULL
  AND (
    users.partner_type = 0
    AND products.is_quantity_supplier = 1 OR products.storehouse_ids && ARRAY[1]
    AND line_items.pre_order_at IS NOT NULL
  )
');

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