Some varray examples-manipulating collections, PL-SQL Programming

Some Varray Examples

In SQL Plus, assume that you define an object type Project, as described below:

SQL> CREATE TYPE Project AS OBJECT (
2 project_no NUMBER(2),
3 title VARCHAR2(35),
4 cost NUMBER(7,2));


After that, you define VARRAY type ProjectList that stores the Project objects:

SQL> CREATE TYPE ProjectList AS VARRAY(50) OF Project;


At last, you create relational table department that has a column of the type ProjectList, as shown:

SQL> CREATE TABLE department (
2 dept_id NUMBER(2),
3 name VARCHAR2(15),
4 budget NUMBER(11,2),
5 projects ProjectList);


Each and every item in the column projects is the varray that will store the scheduled projects for a given department. Now, you are ready to populate the relational table department. In the illustration below, notice that how the varray constructor ProjectList() gives values for the column projects:


BEGIN
INSERT INTO department
VALUES(30, ’Accounting’, 1205700,
ProjectList(Project(1, ’Design New Expense Report’, 3250),
Project(2, ’Outsource Payroll’, 12350),
Project(3, ’Evaluate Merger Proposal’, 2750),
Project(4, ’Audit Accounts Payable’, 1425)));
INSERT INTO department
VALUES(50, ’Maintenance’, 925300,
ProjectList(Project(1, ’Repair Leak in Roof’, 2850),
Project(2, ’Install New Door Locks’, 1700),
Project(3, ’Wash Front Windows’, 975),
Project(4, ’Repair Faulty Wiring’, 1350),
Project(5, ’Winterize Cooling System’, 1125)));
INSERT INTO department
VALUES(60, ’Security’, 750400,
ProjectList(Project(1, ’Issue New Employee Badges’, 13500),
Project(2, ’Find Missing IC Chips’, 2750),
Project(3, ’Upgrade Alarm System’, 3350),
Project(4, ’Inspect Emergency Exits’, 1900)));
END;


In the illustration below, you update the list of the projects assigned to the Security Department:



DECLARE
new_projects ProjectList :=
ProjectList(Project(1, ’Issue New Employee Badges’, 13500),
Project(2, ’Develop New Patrol Plan’, 1250),
Project(3, ’Inspect Emergency Exits’, 1900),
Project(4, ’Upgrade Alarm System’, 3350),
Project(5, ’Analyze Local Crime Stats’, 825));
BEGIN
UPDATE department
SET projects = new_projects WHERE dept_id = 60;
END;


In the next illustration, you recover all the projects for the Accounting Department into a local varray:


DECLARE
my_projects ProjectList;
BEGIN
SELECT projects INTO my_projects FROM department
WHERE dept_id = 30;
...
END;


In the final illustration, you delete the Accounting Department and its project list from the table department:

BEGIN
DELETE FROM department WHERE dept_id = 30;
END;

Posted Date: 10/3/2012 6:43:03 AM | Location : United States







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