I've had a few people visit the site looking for some help on the Oracle 9i TABLE command. With this, you can issue SELECT statements against PL/SQL tables.
Now, previously I'd posted about the self same command, in a series of posts here:
http://robertbaillie.blogspot.com/2005/07/in-thing.htmlhttp://robertbaillie.blogspot.com/2005/07/in-thing-example.htmlhttp://robertbaillie.blogspot.com/2005/07/in-thing-simpler-example.htmlSoon, I plan to put a few more notes together, starting from a simpler example. But for now I'll just thank Amis for the post
here, which has pointed out a complexity in my own example that I didn't realise...
For some reason, the TABLE command cannot work out the data type of variable passed to it, and so will tend to throw an exception:
ORA-22905: cannot access rows from a non-nested table item
As I'd only ever done this when working with package, I previously worked around this by coding a function that returns the content of the relevent package variable. TABLE has no problem working out the datatype returned from a function.
It turns out I could have got away with just a simple CAST.
E.G. SELECT * FROM TABLE( CAST( table_variable AS table_type ) )
So, with that in mind, the first
'In Thing' example becomes this:
The Example:
In order to have something to access, we need the tables and data:
CREATE TABLE product
( id NUMBER
, descr VARCHAR2( 100 ) )
/
INSERT INTO product ( id, descr ) VALUES ( 1, 'one' );
INSERT INTO product ( id, descr ) VALUES ( 2, 'two' );
INSERT INTO product ( id, descr ) VALUES ( 3, 'three' );
INSERT INTO product ( id, descr ) VALUES ( 4, 'four' );
INSERT INTO product ( id, descr ) VALUES ( 5, 'five' );
INSERT INTO product ( id, descr ) VALUES ( 6, 'six' );
COMMIT;
In order to perform the cast we need to declare a type for the row in the table, and then the table type itself:
CREATE TYPE gt_id_type AS OBJECT ( id NUMBER )
/
CREATE TYPE gt_id_list_type AS TABLE OF gt_id_type
/
Then we define the package that will perform the cast.
We have the following functions
- GET_PRODUCTS, which is passed a table of IDs, and returns a ref cursor containing the products requested.
- GET_PRODS_BY_NAME, which is passed a string, and returns all the products that have a description containing that string. This function uses GET_PRODUCTS to return the product details
CREATE OR REPLACE PACKAGE product_pkg AS
TYPE gt_product_cur IS REF CURSOR;
FUNCTION get_products ( pt_id_list gt_id_list_type )
RETURN gt_product_cur;
FUNCTION get_prods_by_name ( pc_product_name VARCHAR2 )
RETURN gt_product_cur;
END;
/
CREATE OR REPLACE PACKAGE BODY product_pkg AS
--
gt_id_list gt_id_list_type;
--
FUNCTION get_products
( pt_id_list gt_id_list_type )
RETURN gt_product_cur IS
--
vt_product_cur gt_product_cur;
--
BEGIN
--
gt_id_list := pt_id_list;
--
OPEN vt_product_cur FOR
SELECT *
FROM product
WHERE id IN ( SELECT id
FROM TABLE( CAST( gt_id_list AS gt_id_list_type ) ) );
--
RETURN vt_product_cur;
--
END;
--
FUNCTION get_prods_by_name
( pc_product_name VARCHAR2 )
RETURN gt_product_cur IS
--
vt_product_ids gt_id_list_type;
--
BEGIN
--
SELECT gt_id_type( id )
BULK COLLECT
INTO vt_product_ids
FROM product
WHERE descr LIKE '%'|| pc_product_name|| '%';
--
RETURN get_products( vt_product_ids );
--
END;
--
END;
/
Finally, we have some code to run the GET_PRODS_BY_NAME function and return its set of values.
SET SERVEROUTPUT ON SIZE 1000000
DECLARE
--
vt_cur product_pkg.gt_product_cur;
vr_product_rec product%ROWTYPE;
--
BEGIN
--
vt_cur := product_pkg.get_prods_by_name( 't' );
--
LOOP
--
FETCH vt_cur INTO vr_product_rec;
EXIT WHEN vt_cur%NOTFOUND;
DBMS_OUTPUT.PUT_LINE( vr_product_rec.descr );
--
END LOOP;
--
END;
/
And the output:
two
three
Disclaimer: I've not yet managed to test this out with access from a PHP layer...
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