Re: My First Stored Procedure

Hi all,

After some more work I've managed to answer my original question - And now have a fully fleshed out function that I think should do everything I want - Except I'm having trouble calling it.

I am calling using:

SELECT insert_period(1::INTEGER,'2005-09-13'::DATE,'2005-09-15'::DATE,'unavailable_periods');

But am getting the error message:

-----

ERROR: syntax error at or near "$1" at character 70
QUERY: SELECT * FROM bookings WHERE (start_date, end_date) OVERLAPS (DATE $1 - interval '1 day', DATE $2 + interval '1 day') AND property_id = $3 LIMIT 1
CONTEXT: PL/pgSQL function "insert_period" line 12 at select into variables
------

I've used EMS PostgreSQL Manager to write the function, and have successfully used the debugger to step through the function using various calling arguments without issues - I only get this problem when trying to call the function through a client.

Research on this revealed problems when variable names are named after existing postgres functions/tables/columns, but I to my knowledge there is nothing in the database named the same of my arguments. I've tried renaming them all to random names, but to no avail. I've also tried declaring the variables as ALIAS FOR in the DECLARE section, but again no luck. The other thing that concerns me is that the error shows $1 being used as a DATE argument, I would have thought 'prop_id' (See below) would have been $1?

I have included the function below - Anyone have any ideas?

Cheers,

Neil.

-----

CREATE OR REPLACE FUNCTION "public"."insert_period" (prop_id integer, new_start_date date, new_end_date date, into_table varchar) RETURNS integer AS

$body$

DECLARE

cur_overlap refcursor;

new_id INTEGER;

num_entries INTEGER;

row_one record;

row_two record;

clashes record;

BEGIN

LOCK TABLE calendar_entries IN EXCLUSIVE MODE;

SELECT INTO clashes * FROM bookings WHERE (start_date, end_date) OVERLAPS (DATE new_start_date - interval '1 day', DATE new_end_date + interval '1 day') AND property_id = prop_id LIMIT 1;

IF NOT FOUND THEN

DELETE FROM calendar_entries WHERE property_id = prop_id AND (start_date >= new_start_date) AND (end_date <= new_end_date);

OPEN cur_overlap FOR SELECT *, pg_class.relname AS table FROM calendar_entries WHERE (start_date, end_date) OVERLAPS (new_start_date - interval '2 days', new_end_date + interval '2 days') AND property_id = prop_id AND pg_class.oid = tableoid ORDER BY start_date;

GET DIAGNOSTICS num_entries = ROW_COUNT;

IF (num_entries = 1) THEN

/* We're overlapping one row. Either we're enveloped by a single row,

or we have one row overlapping either the start date or the end

date.

*/

FETCH cur_overlap INTO row_one;

IF (row_one.start_date <= new_start_date) AND (row_one.end_date >= new_end_date) THEN

/* We're enveloped. The enveloping row needs to be split in to

two so that we can insert ourselves. */

IF row_one.table = into_table THEN

/* This period is already marked appropriately. Do nothing. */

ELSE

/* We need to perform a split/insert.

1. Adjust the end date of the enveloping row to the new

start - 1 day.

2. Insert a new row as the same type as the enveloping row

from new_end_date + 1 to the existing end date.

3. Insert the new row in to the required table */

EXECUTE 'UPDATE ' || row_one.table || ' SET end_date = DATE ''' || new_start_date || ''' - interval ''1 day'' WHERE id = ' || row_one.id;

EXECUTE 'INSERT INTO ' || row_one.table || ' (start_date, end_date) VALUES (DATE ''' || new_end_date || ''' + interval ''1 day'', DATE ''' || row_one.end_date || ''')';

EXECUTE 'INSERT INTO ' || into_table || ' (start_date, end_date) VALUES (DATE ''' || new_start_date || ''', DATE ''' || new_end_date || ''')';

END IF;

ELSIF row_one.start_date <= new_start_date THEN

/* This row is earlier than the proposed period - It's overlapping

our start date - But is it of the same type? */

IF row_one.table = into_table THEN

/* A single row overlapping the start only and of the same

type - Update the end date and return the existing row ID */

EXECUTE 'UPDATE ' || into_table || ' SET end_date = ' || DATE || '''' || new_end_date || ''' WHERE id = ' || row_one.id;

RETURN row_one.id;

ELSE

/* Single row, overlapping the start, and of a different type.

Trim back the existing row and Insert and return

newly generated ID. */

EXECUTE 'INSERT INTO ' || into_table || '(start_date, end_date) VALUES (DATE ''' || new_start_date || ''', DATE ''' || new_end_date || ''')';

new_id = EXECUTE('SELECT currval(''calendar_entry_id_seq'')');

RETURN new_id;

END IF;

ELSIF row_one.start_date > new_end_date THEN

/* This period is after the proposed period */

IF row_one.table = into_table THEN

/* Single row, overlapping the end, and of the same type.

Update the start_date of the existing row, and return it's

id. */

EXECUTE 'UPDATE ' || into_table || ' SET start_date = DATE ''' || new_start_date || ''' WHERE id = ' || row_one.id;

RETURN row_one.id;

ELSE

/* Single row, overlapping the end, and of a different type.

Update the existing rows start_date, insert a new row,

and return the new ID. */

EXECUTE 'UPDATE ' || into_table || ' SET start_date = DATE ''' || new_end_date || ''' + interval ''1 day''';

EXECUTE 'INSERT INTO ' || into_table || ' (start_date, end_date) VALUES (DATE ''' || new_start || ''',DATE ''' || new_end || ''')';

new_id = EXECUTE('SELECT currval(''calendar_entry_id_seq'')');

RETURN new_id;

END IF;

END IF;

ELSIF (num_entries = 2) THEN

FETCH cur_overlap INTO row_one;

FETCH cur_overlap INTO row_two;

/* Two rows */

IF (row_one.table = into_table) AND (row_two.table = into_table) THEN

/* Two overlapping/adjactent rows, both of the same type as the

new entry. Delete the second row, and adjust the end_date of

the first to stretch across until the end o the old second

row.

*/

EXECUTE 'DELETE FROM ' || into_table || ' WHERE id = ' || row_two.id;

EXECUTE 'UPDATE ' || into_table || ' SET end_date = ' || row_two.end_date || ' WHERE id = ' || row_one.id;

RETURN row_one.id;

ELSIF row_one.table = into_table THEN

/* Two overlapping/adjacent rows, only the row overlapping the

start is of the same type. Adjust the end date of this row to

be the end date of the new row.*/

EXECUTE 'UPDATE ' || into_table || ' SET end_date = DATE''' || new_end_date || ''' WHERE id = ' || row_one.id;

RETURN row_one.id;

ELSIF row_two.table = into_table THEN

/* Two overlapping/adjacent rows, only the row overlapping the

end is of the same type. Adjust the start date of this row

to be the start date of the new row.*/

EXECUTE 'UPDATE ' || into_table || ' SET start_date = DATE ''' || new_start_date || ''' WHERE id = ' || row_two.id;

RETURN row_two.id;

ELSE

/* Two overlapping/adjacent rows, neither of which are of the

same type as the new row */

EXECUTE 'INSERT INTO ' || into_table || ' (start_date, end_date) VALUES (DATE ''' || new_start_date || ''', DATE ''' || new_end_date || ''')';

new_id = EXECUTE("SELECT currval('calendar_entry_id_seq')");

RETURN new_id;

END IF;

END IF;

ELSE

RAISE EXCEPTION 'Operation aborted: Clashing booking detected';

END IF;

END;

$body$

LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;

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