PostgreSQL stored procedure: How to insert from a variable - stored-procedures

Question

I am trying to write a stored procedure which parses the input JSON into a record and populates the various tables with JSON content. The problem is that I cannot figure out how to use a variable in INSERT. My table, type and the stored procedure are defined as:
REATE TYPE resource_raw AS (
"field1" text ,
"field2" text ,
"field3" text,
"field4" text
};
CREATE TABLE IF NOT EXISTS actual_table (
field1 text,
field2 text
};
CREATE OR REPLACE FUNCTION discovery_graph.populate_resource(json_in json)
RETURNS resource_raw AS
$BODY$DECLARE
raw_record resource_raw;
BEGIN
SELECT json_populate_record( NULL::resource_raw, json_in) INTO raw_record;
INSERT INTO actual_table (field1, field2) SELECT (field1, field2) FROM raw_record;
RETURN raw_record;
END;
$BODY$
LANGUAGE plpgsql VOLATILE;
The problem is that when I execute the procedure I get an error:
ERROR: relation "raw_record" does not exist
LINE 1: ...field1, field2) FROM raw_record
I am wondering what I am doing wrong in using the variable for INSERT?

Answer 1

You cannot use FROM raw_record in your INSERT as raw_record is not a table. This will run without errors:
CREATE OR REPLACE FUNCTION populate_resource(json_in json)
RETURNS resource_raw AS
$BODY$DECLARE
raw_record resource_raw;
BEGIN
SELECT json_populate_record(NULL::resource_raw, json_in) INTO raw_record;
INSERT INTO actual_table (field1, field2) (SELECT raw_record.field1, raw_record.field2);
RETURN raw_record;
END;
$BODY$
LANGUAGE plpgsql VOLATILE;
More detailed info about the variables in the documentation, for example: 40.10. PL/pgSQL Under the Hood - variable substitution