postgresql - Updating a PostgreSQL table from a CSV file

Question

I am trying to find a way to automatically update data from a csv file on a PostgreSQL table.

The csv file holds LabVIEW test data, which will renew with every execution and is stored on the local computer.

So far I am able to import data from the csv into table 'test1' using 2 methods:

1. COPY command

   COPY test1 FROM 'C:\Users\..\Test.csv' DELIMITER E'\t' CSV;
   

2. Foreign Data Wrappers (file_fdw)

   CREATE SERVER labview FOREIGN DATA WRAPPER file_fdw;
   
   CREATE FOREIGN TABLE labview_test (
   column1 text
   )
   SERVER labview OPTIONS (filename 'C:\Users\..\Test.csv', format 'csv');
   

From there I can insert data into test1 using

    INSERT INTO test1 (column1) FROM labview_test;

This is ok for a single update, but I need this process to be automated. I tried using triggers and trigger functions and I am able to create the trigger on the foreign table, but the table does not update when I run a new LabVIEW test.

   CREATE FUNCTION copy_test ()
   RETURNS TRIGGER AS $$
   BEGIN
   INSERT INTO test1 VALUES (NEW.column1);
   RETURN NULL;
   END $$ LANGUAGE plpgsql;


   CREATE TRIGGER copy_trigger
   AFTER INSERT OR UPDATE ON labview_test
   FOR EACH ROW
   EXECUTE PROCEDURE copy_test ();

I read on a forum post that file_fdw does not support the trigger function, can anyone confirm this in the latest version of PostgreSQL (9.6)?

Does anyone know of a way to automatically update tables from a foreign table or from the .csv file directly?

Answer 1

您不能在外部表上放置触发器，但是....

您可以创建外部表的物化视图。然后，您可以在物化视图上放置触发器。最后，您可以让外部调度程序刷新物化视图（与数据同时），这应该会导致触发器在新数据上触发。