Re: How to insert into 2 tables from a view?

On Tue, 2014-12-23 at 15:00 -0500, Chris Hoover wrote:
> Sorry, in my haste to get the example out, a couple of typo's where in
> the sql.
>
>
> Correct sql:
> BEGIN;
>
>
> CREATE TABLE table1 (
>
> table1_id SERIAL PRIMARY KEY,
> table1_field1 TEXT
> );
>
>
> CREATE TABLE table2 (
> table1_id INTEGER NOT NULL PRIMARY KEY REFERENCES table1(table1_id)
> ON DELETE CASCADE,
> table2_field1 TEXT
> );
>
>
> CREATE VIEW orig_table AS
> SELECT table1_id, table1_field1, table2_field1
> FROM table1
> JOIN table2 USING (table1_id);
>
>
> CREATE FUNCTION orig_table_insert(in_table1_id integer,
> in_table1_field1 text, in_table2_field1 text)
> RETURNS SETOF orig_table
> LANGUAGE plpgsql
> AS
> $BODY$
> DECLARE
> v_table1_id table1.table1_id%TYPE;
> BEGIN
> INSERT INTO table1 (
> table1_id, table1_field1
> ) VALUES (
> COALESCE(in_table1_id, NEXTVAL('table1_table1_id_seq')),
> in_table1_field1
> )
> RETURNING table1_id
> INTO v_table1_id;
>
>
> INSERT INTO table2 (
> table1_id, table2_field1
> ) VALUES (
> v_table1_id, in_table2_field1
> );
>
>
> RETURN QUERY SELECT table1_id, table1_field1, table2_field1
> FROM orig_table
> WHERE table1_id = v_table1_id;
>
>
> END;
> $BODY$;
>
>
>
> CREATE RULE orig_table_insert_rule AS
> ON INSERT
> TO orig_table
> DO INSTEAD
> SELECT orig_table_insert(NEW.table1_id, NEW.table1_field1,
> NEW.table2_field1);
>
>
> COMMIT;
>
>
> Problem query:
> insert into orig_table (table1_field1, table2_field1) values
> ('field1', 'field2') returning table1_id;
>
>
>
>
> On Tue, Dec 23, 2014 at 1:46 PM, Chris Hoover <revoohc(at)gmail(dot)com>
> wrote:
> Hi,
>
>
> I am having a problem trying to figure out.
>
>
> I have two tables behind a view and am trying to figure out
> how to create the correct insert rule so that inserting into
> the view is redirected to the two tables. I thought I had is
> solved using a stored procedure, but doing an insert into
> view ... returning id causes the insert to fail with this
> error:
>
>
>
> ERROR: cannot perform INSERT RETURNING on relation
> "orig_view"
> HINT: You need an unconditional ON INSERT DO INSTEAD rule
> with a RETURNING clause
>
>
> We are running pg 9.0 and I think this version of PG is the
> bottleneck to getting this done. Does anyone know how to get
> around it? Below is a basic example demonstrating what we are
> wanting to do.
>
>
> CREATE TABLE table1 (
>
> table1_id SERIAL PRIMARY KEY,
> table1_field1 TEXT
> );
>
>
> CREATE TABLE table2 (
> table1_id INTEGER NOT NULL PRIMARY KEY REFERENCES
> table1(table1_id) ON DELETE CASCADE,
> table2_field1 TEXT
> );
>
>
> CREATE VIEW orig_table AS
> SELECT table1_id, table1_field_1, table2_field1
> FROM table1
> JOIN table2 USING (table1_id);
>
>
> CREATE FUNCTION orig_table_insert(in_table1_id integer,
> in_table1_field1 text, in_table2_field1 text)
> RETURNS SETOF orig_table
> LANGUAGE plpgsql
> AS
> $BODY$
> DECLARE
> v_table1_id table1.table1_id%TYPE
> BEGIN
> INSERT INTO table1 (
> table1_id, table1_field1
> ) VALUES (
> in_table1_id, in_table1_field1
> )
> RETURNING table1_id
> INTO v_table1_id;
>
>
> INSERT INTO table2 (
> table1_id, table2_field1
> ) VALUES (
> v_table_id, in_table2_field1
> );
>
>
> RETURN QUERY SELECT table1_id, table1_field1,
> table2_field1
> FROM orig_table
> WHERE table1_id = v_table1_id;
>
>
> END;
> $BODY$;
>
>
>
> CREATE RULE orig_table_insert_rule AS
> ON INSERT
> TO orig_table
> DO INSTEAD
> SELECT orig_table_insert(NEW.table1_id,
> NEW.table1_field1, NEW.table2_field1);
>
>
> Thanks,
>
>
> Chris
>
>

Defining a column as SERIAL will automatically create a sequence. You do
not need to supply a value. So:-

INSERT INTO table1 (table1_field1) VALUES (in_table1_field1);
SELECT lastval() INTO last_row_id;

will cause last_row_id to contain the value automatically assigned to
column table1_id. Then you can:-

INSERT INTO table2 (table1_id, table2_field1) VALUES (last_row_id,
in_table2_field1);

You could put this into a function returning an integer. If an error
occurred then it could return zero, otherwise the value of last_row_id.

You need to work out how to handle any errors. Inside the function you
can use BEGIN . . WHEN OTHERS . . END; but eventually you have to
display the error to your users and you haven't mentioned how the
application will do this, or indeed the language being used.

I can vaguely remember that in version 9.0 you have to use dollar quoted
variables so the first insert would become:-

INSERT INTO table1 (table1_field1) VALUES ($1);

Rather strange to have two tables sharing the same primary key value.
One would have thought it was a one-to-many relationship between table1
and table2.

HTH.

Rob