Oracle PL/SQL Tutorial/Cursor/Cursor Open

An example of opening a cursor variable

SQL>
SQL>
SQL> create table product(
  2     product_id number(4)     not null,
  3     product_description varchar2(20) not null
  4  );
Table created.
SQL>
SQL> insert into product values (1,"Java");
1 row created.
SQL> insert into product values (2,"Oracle");
1 row created.
SQL> insert into product values (3,"C#");
1 row created.
SQL> insert into product values (4,"Javascript");
1 row created.
SQL> insert into product values (5,"Python");
1 row created.
SQL>
SQL>
SQL> DECLARE
  2    TYPE rc is REF CURSOR;
  3    refCursorValue rc;
  4  BEGIN
  5    OPEN refCursorValue FOR SELECT * from product;
  6    /*...FETCH the results and process the resultset */
  7    null;
  8  END;
  9  /
PL/SQL procedure successfully completed.
SQL>
SQL> drop table product;
Table dropped.

Open cursor with a dynamic select statement

SQL>
SQL> CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
  2                    ENAME VARCHAR2(10),
  3                    JOB VARCHAR2(9),
  4                    MGR NUMBER(4),
  5                    HIREDATE DATE,
  6                    SAL NUMBER(7, 2),
  7                    COMM NUMBER(7, 2),
  8                    DEPTNO NUMBER(2));
Table created.
SQL>
SQL> INSERT INTO EMP VALUES (7369, "SMITH", "CLERK",    7902, TO_DATE("17-DEC-1980", "DD-MON-YYYY"), 800, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7499, "ALLEN", "SALESMAN", 7698, TO_DATE("20-FEB-1981", "DD-MON-YYYY"), 1600, 300, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7521, "WARD",  "SALESMAN", 7698, TO_DATE("22-FEB-1981", "DD-MON-YYYY"), 1250, 500, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7566, "JONES", "MANAGER",  7839, TO_DATE("2-APR-1981",  "DD-MON-YYYY"), 2975, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7654, "MARTIN", "SALESMAN", 7698,TO_DATE("28-SEP-1981", "DD-MON-YYYY"), 1250, 1400, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7698, "BLAKE", "MANAGER", 7839,TO_DATE("1-MAY-1981", "DD-MON-YYYY"), 2850, NULL, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7782, "CLARK", "MANAGER", 7839,TO_DATE("9-JUN-1981", "DD-MON-YYYY"), 2450, NULL, 10);
1 row created.
SQL> INSERT INTO EMP VALUES (7788, "SCOTT", "ANALYST", 7566,TO_DATE("09-DEC-1982", "DD-MON-YYYY"), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7839, "KING", "PRESIDENT", NULL,TO_DATE("17-NOV-1981", "DD-MON-YYYY"), 5000, NULL, 10);
1 row created.
SQL> INSERT INTO EMP VALUES (7844, "TURNER", "SALESMAN", 7698,TO_DATE("8-SEP-1981", "DD-MON-YYYY"), 1500, 0, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7876, "ADAMS", "CLERK", 7788,TO_DATE("12-JAN-1983", "DD-MON-YYYY"), 1100, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7900, "JAMES", "CLERK", 7698,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 950, NULL, 30);
1 row created.
SQL> INSERT INTO EMP VALUES (7902, "FORD", "ANALYST", 7566,TO_DATE("3-DEC-1981", "DD-MON-YYYY"), 3000, NULL, 20);
1 row created.
SQL> INSERT INTO EMP VALUES (7934, "MILLER", "CLERK", 7782,TO_DATE("23-JAN-1982", "DD-MON-YYYY"), 1300, NULL, 10);
1 row created.
SQL>
SQL>
SQL> CREATE OR REPLACE PROCEDURE showemps (where_in IN VARCHAR2 := NULL)
  2  IS
  3     TYPE cv_typ IS REF CURSOR;
  4     cv cv_typ;
  5     v_nm emp.ename%TYPE;
  6  BEGIN
  7     OPEN cv FOR
  8        "SELECT ename FROM emp WHERE " || NVL (where_in, "1=1");
  9     LOOP
 10        FETCH cv INTO v_nm;
 11        EXIT WHEN cv%NOTFOUND;
 12        DBMS_OUTPUT.PUT_LINE (v_nm);
 13     END LOOP;
 14     CLOSE cv;
 15  END;
 16  /
Procedure created.
SQL>
SQL> show error
No errors.
SQL>
SQL> EXEC showemps(null);
SMITH
ALLEN
WARD
JONES
MARTIN
BLAKE
CLARK
SCOTT
KING
TURNER
ADAMS
JAMES
FORD
MILLER
PL/SQL procedure successfully completed.
SQL>
SQL>
SQL> drop table emp;
Table dropped.
SQL>

Opening multiple queries using the same cursor variable

SQL> create table product(
  2     product_id number(4)     not null,
  3     product_description varchar2(20) not null
  4  );
Table created.
SQL>
SQL> insert into product values (1,"Java");
1 row created.
SQL> insert into product values (2,"Oracle");
1 row created.
SQL> insert into product values (3,"C#");
1 row created.
SQL> insert into product values (4,"Javascript");
1 row created.
SQL> insert into product values (5,"Python");
1 row created.
SQL>
SQL>
SQL> create table company(
  2     product_id        number(4)    not null,
  3     company_id          NUMBER(8)    not null,
  4     company_short_name  varchar2(30) not null,
  5     company_long_name   varchar2(60)
  6  );
Table created.
SQL> insert into company values(1,1001,"A Inc.","Long Name A Inc.");
1 row created.
SQL> insert into company values(1,1002,"B Inc.","Long Name B Inc.");
1 row created.
SQL> insert into company values(1,1003,"C Inc.","Long Name C Inc.");
1 row created.
SQL> insert into company values(2,1004,"D Inc.","Long Name D Inc.");
1 row created.
SQL> insert into company values(2,1005,"E Inc.","Long Name E Inc.");
1 row created.
SQL> insert into company values(2,1006,"F Inc.","Long Name F Inc.");
1 row created.
SQL>
SQL> DECLARE
  2    TYPE rc is REF CURSOR;
  3    refCursorValue rc;
  4    productRecord product%ROWTYPE;
  5    v_product_description VARCHAR2(20);
  6    v_company_short_name VARCHAR2(30);
  7  BEGIN
  8    OPEN refCursorValue FOR SELECT *from product;
  9
 10    LOOP
 11      FETCH refCursorValue INTO productRecord;
 12      EXIT WHEN refCursorValue%NOTFOUND;
 13      dbms_output.put_line(to_char(productRecord.product_id)||" "||
 14      rpad(productRecord.product_description,20," "));
 15    END LOOP;
 16
 17    OPEN refCursorValue FOR SELECT h.product_description,o.rupany_short_name
 18                  FROM company o,product h
 19                  WHERE o.product_id =h.product_id;
 20
 21    LOOP
 22      FETCH refCursorValue INTO v_product_description,v_company_short_name;
 23      EXIT WHEN refCursorValue%NOTFOUND;
 24      dbms_output.put_line(rpad(v_product_description,20," ")||" "||rpad(v_company_short_name,30," "));
 25    END LOOP;
 26    CLOSE refCursorValue;
 27  END;
 28  /
1 Java
2 Oracle
3 C#
4 Javascript
5 Python
Java                 A Inc.
Java                 B Inc.
Java                 C Inc.
Oracle               D Inc.
Oracle               E Inc.
Oracle               F Inc.
PL/SQL procedure successfully completed.
SQL>
SQL>
SQL> drop table product;
Table dropped.
SQL> drop table company;
Table dropped.
SQL>