1. Chapter 10 Oracle9i Developer: PL/SQL Programming
Introduction to Dynamic
SQL and Object Technology

2. Objectives
Create dynamic SQL
Use object technology

3. Brewbean’s Challenge
Add flexibility to queries such as allowing shoppers to determine if they want to search product names or descriptions
Explore potential capabilities of object technology features for providing greater data consistency and control

4. Dynamic SQL
Allows identifiers such as column and table names to be provided at runtime
Two mechanisms available:
DBMS_SQL package
(Oracle7)
Native dynamic SQL
(Oracle8)

5. DBMS_SQL – DML Example CREATE OR REPLACE PROCEDURE dyn_dml_sp
(p_col VARCHAR2,
p_price NUMBER,
p_id NUMBER) IS
lv_cursor INTEGER;
lv_update VARCHAR2(150);
lv_rows NUMBER(1);
BEGIN
--Open Cursor
lv_cursor := DBMS_SQL.OPEN_CURSOR;

6. DBMS_SQL (continued) --Create DML statement
lv_update := 'UPDATE bb_product
SET ' || p_col || ' = :ph_price
WHERE idProduct = :ph_id';
--Parse the statement
DBMS_SQL.PARSE(lv_cursor, lv_update, DBMS_SQL.NATIVE);
--Associate parameters with placeholders in the statement
DBMS_SQL.BIND_VARIABLE(lv_cursor, ':ph_price', p_price);
DBMS_SQL.BIND_VARIABLE(lv_cursor, ':ph_id', p_id);

7. DBMS_SQL (continued) --Run the DML statement
lv_rows := DBMS_SQL.EXECUTE(lv_cursor);
--Close the cursor
DBMS_SQL.CLOSE_CURSOR(lv_cursor);
--Save changes
COMMIT;
--Check how many rows affected
DBMS_OUTPUT.PUT_LINE(lv_rows);
END;

8. DBMS_SQL

9. DBMS_SQL – Query Example
CREATE OR REPLACE PROCEDURE dyn_query1_sp
(p_col IN VARCHAR2,
p_value IN VARCHAR2) IS
lv_query LONG;
lv_status INTEGER;
lv_cursor INTEGER;
lv_col1 NUMBER(2);
lv_col2 VARCHAR2(25);
lv_col3 NUMBER(6,2);
lv_col4 NUMBER(5,1);

10. DBMS_SQL (continued) BEGIN --Open the cursor
lv_cursor := DBMS_SQL.OPEN_CURSOR;
--Build the query
lv_query := 'SELECT idProduct, productname, price, stock
FROM bb_product
WHERE '|| UPPER(p_col) ||' = ' ||
'UPPER(:ph_value)';
--Parse the statement
DBMS_SQL.PARSE(lv_cursor, lv_query, DBMS_SQL.NATIVE);
--Identify data types for each item selected
DBMS_SQL.DEFINE_COLUMN(lv_cursor, 1, lv_col1);
DBMS_SQL.DEFINE_COLUMN(lv_cursor, 2, lv_col2, 25);
DBMS_SQL.DEFINE_COLUMN(lv_cursor, 3, lv_col3);
DBMS_SQL.DEFINE_COLUMN(lv_cursor, 4, lv_col4);

11. DBMS_SQL (continued) --Associate placeholder with a parameter
DBMS_SQL.BIND_VARIABLE(lv_cursor, ':ph_value', p_value);
--Execute the query
lv_status := DBMS_SQL.EXECUTE(lv_cursor);
--Fetch row returned and place into PL/SQL variables
IF (DBMS_SQL.FETCH_ROWS(lv_cursor) > 0) THEN
DBMS_SQL.COLUMN_VALUE(lv_cursor, 1, lv_col1);
DBMS_SQL.COLUMN_VALUE(lv_cursor, 2, lv_col2);
DBMS_SQL.COLUMN_VALUE(lv_cursor, 3, lv_col3);
DBMS_SQL.COLUMN_VALUE(lv_cursor, 4, lv_col4);
DBMS_OUTPUT.PUT_LINE(lv_col1||' '||lv_col2||'
'||lv_col3||' '||lv_col4);
END IF;
--Close cursor
DBMS_SQL.CLOSE_CURSOR(lv_cursor);
END;

12. DBMS_SQL

13. Native Dynamic SQL Simpler coding More efficient processing
Limited capabilities compared to DBMS_SQL package
Two methods:
EXECUTE IMMEDIATE
OPEN FOR

14. Native Dynamic SQL Example
CREATE OR REPLACE PROCEDURE dyn_query3_sp
(p_col IN VARCHAR2,
p_value IN VARCHAR2) IS
lv_query VARCHAR2(200);
lv_id bb_product.idProduct%TYPE;
lv_name bb_product.productname%TYPE;
lv_price bb_product.price%TYPE;
lv_stock bb_product.stock%TYPE;
BEGIN
--use a variable to hold the query construction to
-- make it more readable

15. Native Dynamic SQL (continued)
lv_query := 'SELECT idProduct, productname, price, stock
FROM bb_product
WHERE UPPER(' || p_col || ') =
UPPER(:ph_value)';
--Run the dynamic query supplying variables to hold the
-- return values in the INTO clause and associate the
-- parameter to the placeholder with the USING clause
EXECUTE IMMEDIATE lv_query
INTO lv_id, lv_name, lv_price, lv_stock
USING p_value;
DBMS_OUTPUT.PUT_LINE(lv_id||' '||lv_name||' '
||lv_price||' '||lv_stock);
END;

16. Native Dynamic SQL

17. DBMS_SQL vs. Native Dynamic SQL
Use native dynamic SQL when:
The number and types of columns to be used is known
The number and type of bind variables is known
To perform DDL
Executing the statement only once or twice
User-defined types such as object and collections are used (not supported by DBMS_SQL)
Fetching rows of data into PL/SQL records (not supported by DBMS_SQL)
SQL statement is less than 32KB in size

18. Object Technology Object Types Object Methods Object Relations
Object Views

19. Object types Represent an entity such as an address or a person
Defined with attributes and methods
Can be used as a data type for a table column
Can contain multiple data elements or attributes

20. Create an Object Type CREATE OR REPLACE TYPE addr_ot AS OBJECT
(street1 VARCHAR2(25),
street2 VARCHAR2(25),
city VARCHAR2(25),
state CHAR(2),
zip NUMBER(9) );

21. Use Object Type CREATE TABLE bb_order (ord_id NUMBER(4),
cust_id NUMBER(4),
ord_date DATE,
total NUMBER(6,2),
bill_addr addr_ot,
ship_addr addr_ot );

22. Object Type Constructor
DECLARE
lv_bill addr_ot;
lv_ship addr_ot;
BEGIN
lv_bill := addr_ot('11 Bush Dr' ,NULL,
'Savannah', 'GA', );
lv_ship := addr_ot('812 Scott Lane','Apt
#52','Savannah','GA', );
INSERT INTO bb_order
VALUES (102,31,'11-NOV-03’
,34.50,lv_bill,lv_ship);
END;

23. DESCRIBE command

24. Methods Add program units to object types Referred to as members
Similar to package creation
Add function:
ALTER TYPE addr_ot
ADD MEMBER FUNCTION lbl_print RETURN
VARCHAR2;

25. Object Type Body

26. Object Relations Create customer object type:
CREATE TYPE cust_ot AS OBJECT
(cust_id NUMBER(4),
first VARCHAR2(15),
last VARCHAR2(20),
VARCHAR2(25),
phone NUMBER(10) );
Create customer table:
CREATE TABLE bb_cust OF cust_ot
(PRIMARY KEY (cust_id));

27. Object Relations (continued)
Create orders object type:
CREATE TYPE ord_ot AS OBJECT
(ord_id NUMBER(4),
cust_ref REF cust_ot,
ord_date DATE,
total NUMBER(6,2));
CREATE TABLE bb_ord OF ord_ot
(PRIMARY KEY (ord_id));

28. Object Relations (continued)
Use REF variable to establish relation:
INSERT INTO bb_cust
VALUES
));
INSERT INTO bb_ord
SELECT ord_ot(1,REF(c),SYSDATE,24.50)
FROM bb_cust c
WHERE cust_id = 12;
COMMIT;

29. REF pointers
Does not prevent broken relations like a foreign key constraint

30. Object Views
Provide a layer on top of traditional database designs to enable object features
OBJECT OID identifies unique view row identifier
CAST and MULTISET handle subquery mapping to view elements

31. Object View Example CREATE TYPE bask_ot AS OBJECT (idBasket NUMBER(5),
total NUMBER(7,2)) /
CREATE TYPE bask_tab AS TABLE OF bask_ot
CREATE TYPE shop_ot AS OBJECT
(idShopper NUMBER(4),
last_name VARCHAR2(20),
city VARCHAR2(20),
idBasket bask_tab)

32. Object View Example CREATE VIEW shop_vu OF shop_ot
WITH OBJECT OID(idShopper) AS
SELECT s.idShopper, s.lastname, s.city,
CAST(MULTISET(SELECT idBasket, total
FROM bb_basket b
WHERE b.idShopper = s.idShopper)
AS bask_tab)
FROM bb_shopper s;

33. Summary
Dynamic SQL allows identifiers and DDL statements to process within PL/SQL
DBMS_SQL package and native dynamic SQL are two mechanisms providing dynamic SQL capabilities
Native dynamic SQL is simpler to code and executes more efficiently
Object types represent an entity which can contain multiple data attributes and program units

34. Summary Program units in object types are called methods
Relationships between object rows are established using REF variables
Object views provide a mechanism to use object technology features with a traditional database design