Cursor Loop

Cursor Loop
Explicitly declared cursor and record	CREATE ORREPLACE PROCEDURE <procedure_name> IS CURSOR <cursor_name> IS <SQL statement> <record_name> <cursor_name>%ROWTYPE; BEGIN   OPEN <cursor_name>   LOOP     FETCH <cursor_name> INTO <record_name>;     EXIT WHEN <cursor_name>%NOTFOUND;     <other code>   END LOOP;   CLOSE <cursor_name>; END <procedure_name>; /
	TRUNCATETABLE loop_test; DECLARE CURSOR ao_curIS  SELECT SUBSTR(object_name,1,5) FIRSTFIVE  FROM all_objs   WHERE SUBSTR(object_name,1,5) BETWEEN 'A'AND 'M'; ao_rec ao_cur%ROWTYPE; BEGIN   OPEN ao_cur;   LOOP     FETCH ao_curINTO ao_rec;     EXIT WHEN ao_cur%NOTFOUND;     INSERT INTO loop_test VALUES (ao_rec.firstfive);   ENDLOOP;   COMMIT;   CLOSE ao_cur; END; / SELECT COUNT(*) FROM loop_test;
Fetch Demo	-- Demo courtesy of Andy Hassall <[email protected]> CREATE TABLE t1 (tcol NUMBER); CREATE TABLE t2 (c NUMBER); BEGIN   FOR i IN 1..500 LOOP     INSERT INTO t1 VALUES (i);   END LOOP; END; / SELECT COUNT(*) FROM t1; COMMIT; CREATE ORREPLACE FUNCTION p (c_in NUMBER)RETURN NUMBER IS PRAGMA AUTONOMOUS_TRANSACTION; BEGIN   -- Every time this is called, write a row to table t2   INSERT INTO t2 VALUES (c_in);   COMMIT;   RETURN c_in; END p; / DECLARE   BEGIN   /* Open up a cursor for loop, also selecting   * the "p" function which will write rows to   * t2 for every row fetched from t1. */   FOR crec IN (SELECT tcol, p(tcol)FROM t1) LOOP     -- Break out of the loop immediately     EXIT;   END LOOP; END; / SELECT COUNT(*) FROM t2;
Cursor FOR Loop
Explicitly declared cursor and implicit record declared by the FOR loop	CREATE ORREPLACE PROCEDURE <procedure_name> IS CURSOR <cursor_name> IS <SQL statement> BEGIN   FOR <record_name> IN <cursor_name>   LOOP     <other code>   END LOOP; END <procedure_name>; /
	TRUNCATETABLE loop_test; DECLARE  CURSOR ao_curIS    SELECT SUBSTR(object_name,1,5) FIRSTFIVE    FROM all_objs    WHERE SUBSTR(object_name,1,5) BETWEEN 'N'AND 'W'; BEGIN   FOR ao_recIN ao_cur LOOP     INSERT INTO loop_test VALUES (ao_rec.firstfive);   ENDLOOP;   COMMIT; END; / SELECT COUNT(*) FROM loop_test;
A FOR loop with an intrinsic cursor. A record is implicitly declared by the variable in the FOR statement.	BEGIN   FOR <record_name> IN <SQL_statement>   LOOP     <other code>   END LOOP; END <procedure_name>; /
	TRUNCATETABLE loop_test; BEGIN   FOR ao_recIN (     SELECT SUBSTR(object_name,1,5) FIRSTFIVE     FROM all_objs     WHERE SUBSTR(object_name,1,5) BETWEEN 'N'AND 'Z')   LOOP     INSERT INTO loop_test VALUES (ao_rec.firstfive);   ENDLOOP;   COMMIT; END; / SELECT COUNT(*) FROM loop_test;
Cursor Loop With WHERE CURRENT OF Clause	CREATE ORREPLACE PROCEDURE <procedure_name> IS <cursor definition> BEGIN   FOR <record_name> IN (<cursor_name>)   LOOP     <other code>     UPDATE <table_name>     SET <column_name> = <value>     WHERE CURRENT OF <cursor_name>   END LOOP; END <procedure_name>; /
	CREATETABLE test ( pid  NUMBER(3), cash  NUMBER(10,2)); INSERT INTO test VALUES (100, 10000.73); INSERT INTO test VALUES (200  25000.26); INSERT INTO test VALUES (300, 30000.11); INSERT INTO test VALUES (400, 45000.99); INSERT INTO test VALUES (500, 50000.08); COMMIT; CREATE ORREPLACE PROCEDURE wco IS CURSOR x_cur IS SELECT pid, cash FROM test WHERE cash < 35000 FORUPDATE; BEGIN   FOR x_rec IN x_cur LOOP     UPDATE test     SET cash = FLOOR(cash)     WHERE CURRENT OF x_cur;   END LOOP;   COMMIT; END wco; / exec wco; SELECT * FROM test;
Nested Cursor Loops
Demo Tables	CREATETABLE airplanes ( program_id  VARCHAR2(3), line_number NUMBER(10), customer_id VARCHAR2(4), order_date  DATE, delivered_date DATE) PCTFREE 0; CREATE INDEX programid_idx ON airplanes (program_id) PCTFREE 0; CREATE TABLE parts ( program_id VARCHAR2(3), line_type VARCHAR2(4), part_type VARCHAR2(10), quantity NUMBER(3)); CREATE TABLE ap_parts AS SELECT a.customer_id, p.part_type, p.quantity FROM airplanes a, parts p WHERE a.program_id = p.program_id AND 1=2;
Load Airplanes	DECLARE  progid  airplanes.program_id%TYPE;  lineno  airplanes.line_number%TYPE;  custid  airplanes.customer_id%TYPE := 'AAL';  orddate airplanes.order_date%TYPE;  deldate airplanes.delivered_date%TYPE; BEGIN   FOR i IN 1 .. 5 LOOP     SELECT DECODE(i, 1, '737', 2, '747', 3, '757', 4, '767', 5, '777')     INTO progid     FROM DUAL;     FOR lineno IN 1..250 LOOP       SELECT DECODE(custid, 'AAL','DAL','DAL','SAL','SAL','ILC',      'ILC','SWA', 'SWA','NWO','NWO','AAL')       INTO custid       FROM DUAL;     IF progid = '737' THEN       OrdDate := SYSDATE + lineno;       DelDate := OrdDate + lineno + 100;     ELSIF progid = '747' THEN       OrdDate := SYSDATE + lineno+17;       DelDate := OrdDate + lineno + 302;     ELSIF progid = '757' THEN       OrdDate := SYSDATE + lineno+22;       DelDate := OrdDate + lineno + 202;     ELSIF progid = '767' THEN       OrdDate := SYSDATE + lineno+43;       DelDate := OrdDate + lineno + 189;     ELSIF progid = '777' THEN       OrdDate := SYSDATE + lineno-69;       DelDate := OrdDate + lineno + 299;     END IF;       INSERT INTO airplanes       (program_id, line_number, customer_id, order_date,        delivered_date)       VALUES       (progid, lineno, custid, orddate, deldate);     END LOOP;   END LOOP;   COMMIT; END load_airplanes; /
Load Airplane Parts	BEGIN   INSERT INTO parts VALUES ('737', 'Even', 'Wing', 2);   INSERT INTO parts VALUES ('747', 'Even', 'Wing', 2);   INSERT INTO parts VALUES ('757', 'Even', 'Wing', 2);   INSERT INTO parts VALUES ('767', 'EVen', 'Wing', 2);   INSERT INTO parts VALUES ('777', 'even', 'Wing', 2);   INSERT INTO parts VALUES ('737', 'ODD', 'Wing', 2);   INSERT INTO parts VALUES ('747', 'odd', 'Wing', 2);   INSERT INTO parts VALUES ('757', 'Odd', 'Wing', 2);   INSERT INTO parts VALUES ('767', 'Odd', 'Wing', 2);   INSERT INTO parts VALUES ('777', 'Odd', 'Wing', 2);   INSERT INTO parts VALUES ('737', 'Even', 'Galley', 1);   INSERT INTO parts VALUES ('747', 'EVen', 'Galley', 3);   INSERT INTO parts VALUES ('757', 'EVEN', 'Galley', 3);   INSERT INTO parts VALUES ('767', 'EVeN', 'Galley', 2);   INSERT INTO parts VALUES ('777', 'even', 'Galley', 3);   INSERT INTO parts VALUES ('737', 'ODD', 'Galley', 2);   INSERT INTO parts VALUES ('747', 'odd', 'Galley', 4);   INSERT INTO parts VALUES ('757', 'Odd', 'Galley', 3);   INSERT INTO parts VALUES ('767', 'ODd', 'Galley', 4);   INSERT INTO parts VALUES ('777', 'odD', 'Galley', 4);   INSERT INTO parts VALUES ('737', 'Even', 'Tire', 10);   INSERT INTO parts VALUES ('747', 'Even', 'Tire', 18);   INSERT INTO parts VALUES ('757', 'Even', 'Tire', 12);   INSERT INTO parts VALUES ('767', 'Even', 'Tire', 14);   INSERT INTO parts VALUES ('777', 'EveN', 'Tire', 16);   INSERT INTO parts VALUES ('737', 'ODD', 'Tire', 14);   INSERT INTO parts VALUES ('747', 'Odd', 'Tire', 20);   INSERT INTO parts VALUES ('757', 'Odd', 'Tire', 14);   INSERT INTO parts VALUES ('767', 'Odd', 'Tire', 16);   INSERT INTO parts VALUES ('777', 'Odd', 'Tire', 18);   INSERT INTO parts VALUES ('737', 'Even', 'Seats', 105);   INSERT INTO parts VALUES ('747', 'Even', 'Seats', 255);   INSERT INTO parts VALUES ('757', 'Even', 'Seats', 140);   INSERT INTO parts VALUES ('767', 'Even', 'Seats', 200);   INSERT INTO parts VALUES ('777', 'EveN', 'Seats', 210);   INSERT INTO parts VALUES ('737', 'ODD', 'Seats', 137);   INSERT INTO parts VALUES ('747', 'Odd', 'Seats', 20);   INSERT INTO parts VALUES ('757', 'Odd', 'Seats', 166);   INSERT INTO parts VALUES ('767', 'Odd', 'Seats', 345);   INSERT INTO parts VALUES ('777', 'Odd', 'Seats', 267);   COMMIT; END; /
Nested Loops With Static Cursors	CREATE ORREPLACE PROCEDURE nested_loop IS CURSOR a_curIS SELECT program_id,line_number, customer_id FROM airplanes; a_rec a_cur%ROWTYPE; CURSOR p_curIS SELECT part_type, quantity FROM parts WHERE program_id = a_rec.program_id AND UPPER(line_type)=DECODE(MOD(a_rec.line_number,2),0,'EVEN','ODD'); p_rec p_cur%ROWTYPE; BEGIN   OPEN a_cur;   LOOP     FETCH a_cur INTO a_rec;     EXIT WHEN a_cur%NOTFOUND;     OPEN p_cur;     LOOP       FETCH p_cur INTO p_rec;       EXIT WHEN p_cur%NOTFOUND;       INSERT INTO ap_parts       (customer_id, part_type, quantity)       VALUES       (a_rec.customer_id, p_rec.part_type, p_rec.quantity);     END LOOP;     CLOSE p_cur;   ENDLOOP;   COMMIT;   CLOSE a_cur; END nested_loop; /