Oracle - Program with PL/SQL - Lession 05

Working with Composite Data Types

Objectives After completing this lesson, you should be able to do the following: Create user-defined PL/SQL records Create a record with the %ROWTYPE attribute Create an INDEX BY table Create an INDEX BY table of records Describe the difference between records, tables, and tables of records.

Composite Data Types Are of two types: PL/SQL RECORDs PL/SQL Collections – INDEX BY Table – Nested Table – VARRAY Contain internal components Are reusable

PL/SQL Records Must contain one or more components of any scalar, RECORD, or INDEX BY table data type, called fields Are similar in structure to records in a third generation language (3GL) Are not the same as rows in a database table Treat a collection of fields as a logical unit Are convenient for fetching a row of data from a table for processing

Creating a PL/SQL Record Syntax: field_name { field_type | variable%TYPE | table.column%TYPE | table%ROWTYPE } [[NOT NULL] { := | DEFAULT } expr ] Where field_declaration is: TYPE type_name IS RECORD ( field_declaration[, field_declaration]…); identifier type_name;

Creating a PL/SQL Record SET SERVEROUTPUT ON DECLARE TYPE EmpRec IS RECORD ( emp_name VARCHAR2(50), job_title VARCHAR2(9), salary NUMBER(7,2)); emp_info EmpRec; BEGIN SELECT first_name||’ ‘||last_name, job_id, salary INTO emp_info.emp_name, emp_info.job_title, emp_info.salary FROM employees WHERE employee_id = 105; DBMS_OUTPUT.PUT_LINE ('Nhan vien : '||emp_info.emp_name||' lam cong viec '|| emp_info.job_title ||' co muc luong '||emp_info.salary ); END; / Declare variables to store the name, job, and salary of a new employee.

Creating a PL/SQL Record SET SERVEROUTPUT ON DECLARE TYPE EmpRec IS RECORD ( emp_id employees.employee_id%TYPE, job_title VARCHAR2(9), salary NUMBER(7,2)); emp_info EmpRec; emp_null EmpRec; emp EmpRec; BEGIN emp_info.emp_id := 7788; emp_info.job_title := 'ANALYST'; emp_info.salary := 3500; DBMS_OUTPUT.PUT_LINE (‘Ma : ‘||emp_info.emp_id||’-’||emp_info.job_title|| ' - '||emp_info.salary ); emp := emp_info; DBMS_OUTPUT.PUT_LINE (‘Ma : ‘||emp.emp_id||’ – ‘||emp.job_title ||' - '||emp.salary ); emp := emp_null; -- Tat ca cac field trong emp deu co gia tri null DBMS_OUTPUT.PUT_LINE (‘Ma : ‘||emp.emp_id||’ - '||emp.job_title ||' - '||emp.salary ); END; /

The %ROWTYPE Attribute Declare a variable according to a collection of columns in a database table or view. Prefix %ROWTYPE with the database table. Fields in the record take their names and data types from the columns of the table or view.

Advantages of Using %ROWTYPE The number and data types of the underlying database columns need not be known. The number and data types of the underlying database column may change at run time. The attribute is useful when retrieving a row with the SELECT * statement.

The %ROWTYPE Attribute Examples: Declare a variable to store the information about a department from the DEPARTMENTS table. dept_record departments%ROWTYPE; Declare a variable to store the information about an employee from the EMPLOYEES table. emp_record employees%ROWTYPE;

Creating a PL/SQL Record CREATE TABLE e_temp AS SELECT * FROM employees WHERE employee_id = 50; SET SERVEROUTPUT ON DECLARE emp_rec employees%ROWTYPE; BEGIN SELECT * INTO emp_rec FROM employees WHERE employee_id = 105; INSERT INTO e_temp VALUES (emp_rec.employee_id, emp_rec.first_name, emp_rec.last_name, emp_rec.email, emp_rec.phone_number, emp_rec.hire_date, emp_rec.job_id, emp_rec.salary, emp_rec.commission_pct, emp_rec.manager_id, emp_rec.department_id); COMMIT; END; / SELECT * FROM e_temp;

INDEX BY Tables Are composed of two components: – Primary key of data type BINARY_INTEGER – Column of scalar or record data type Can increase in size dynamically because they are unconstrained

Creating an INDEX BY Table TYPE type_name IS TABLE OF { column_type | variable%TYPE | table.column%TYPE } [NOT NULL] | table.%ROWTYPE [INDEX BY BINARY_INTEGER]; identifier type_name; Syntax: ... TYPE ename_table_type IS TABLE OF employees.last_name%TYPE INDEX BY BINARY_INTEGER; ename_table ename_table_type; ... Declare an INDEX BY table to store names. Example:

Creating an INDEX BY Table SET SERVEROUTPUT ON DECLARE TYPE ename_table_type IS TABLE OF employees.last_name%TYPE INDEX BY BINARY_INTEGER; TYPE hiredate_table_type IS TABLE OF DATE INDEX BY BINARY_INTEGER; ename_table ename_table_type; hiredate_table hiredate_table_type; BEGIN ename_table(1) := 'CAMERON'; hiredate_table(8) := SYSDATE + 7; IF ename_table.EXISTS(1) THEN DBMS_OUTPUT.PUT_LINE ( ename_table(1) || ‘ – ‘||hiredate_table(2)); END IF; EXCEPTION WHEN NO_DATA_FOUND THEN DBMS_OUTPUT.PUT_LINE (‘Xu ly loi : ‘|| ename_table(1) || ‘ – ‘ ||hiredate_table(8)); END; /

Using INDEX BY Table Methods The following methods make INDEX BY tables easier to use: – EXISTS – COUNT – FIRST and LAST – PRIOR – NEXT – TRIM – DELETE

INDEX BY Table of Records DECLARE TYPE dept_table_type IS TABLE OF departments%ROWTYPE INDEX BY BINARY_INTEGER; dept_table dept_table_type; -- Each element of dept_table is a record Define a TABLE variable with a permitted PL/SQL data type. Declare a PL/SQL variable to hold department information. Example:

Example of INDEX BY Table of Records SET SERVEROUTPUT ON DECLARE TYPE emp_table_type is table of employees%ROWTYPE INDEX BY BINARY_INTEGER; my_emp_table emp_table_type; v_count NUMBER(3):= 10; BEGIN FOR i IN 1..v_count LOOP SELECT * INTO my_emp_table(i) FROM employees WHERE employee_id = 100 + i; END LOOP; FOR i IN my_emp_table.FIRST..my_emp_table.LAST LOOP DBMS_OUTPUT.PUT_LINE(‘Row : ‘||i ||’ – ‘||my_emp_table(i).last_name || ‘ co muc luong ‘ || my_emp_table(i).salary); END LOOP; END; /

Example of INDEX BY Table of Records SET SERVEROUTPUT ON DECLARE TYPE emp_table_type is table of employees%ROWTYPE INDEX BY BINARY_INTEGER; my_table emp_table_type; v_count NUMBER(3):= 130; BEGIN FOR i IN 100..v_count LOOP SELECT * INTO my_table(i) FROM employees WHERE employee_id = i; END LOOP; IF my_table.exists(99) THEN DBMS_OUTPUT.PUT_LINE(‘Khong ton tai trong bang’); ELSE DBMS_OUTPUT.PUT_LINE(my_table(106).last_name); END IF; END; /

SET SERVEROUTPUT ON DECLARE TYPE emp_table_type is table of employees%ROWTYPE INDEX BY BINARY_INTEGER; my_table emp_table_type; v_count NUMBER(3):= 130; truoc NUMBER(3):= 1; sau NUMBER(3):= 1; BEGIN FOR i IN 100..v_count LOOP SELECT * INTO my_table(i) FROM employees WHERE employee_id = i; END LOOP; DBMS_OUTPUT.PUT_LINE('TEST 1: '||my_table.count); DBMS_OUTPUT.PUT_LINE('Row first: '||my_table.first||' Row last: '||my_table.last); sau := my_table.NEXT(125); truoc := my_table.PRIOR(113); DBMS_OUTPUT.PUT_LINE('Row prior: '||truoc|| ‘ - Row next : ‘||sau); END ;

SET SERVEROUTPUT ON DECLARE TYPE emp_table_type is table of employees%ROWTYPE INDEX BY BINARY_INTEGER; my_table emp_table_type; v_count NUMBER(3):= 130; truoc NUMBER(3):= 1; sau NUMBER(3):= 1; BEGIN FOR i IN 100..v_count LOOP SELECT * INTO my_table(i) FROM employees WHERE employee_id = i; END LOOP; DBMS_OUTPUT.PUT_LINE('TEST 1: '||my_table.count); DBMS_OUTPUT.PUT_LINE('Row first: '||my_table.first||' Row last: '||my_table.last); -- my_table.DELETE; -- Xoa tat ca vung nho cap phat cho my_table -- my_table.DELETE(102); -- Xoa dong 102 my_table.DELETE(100,120); -- Xoa dong 100 --> 120 DBMS_OUTPUT.PUT_LINE ('TEST 2: '||my_table.count); DBMS_OUTPUT.PUT_LINE ('Row first: '||my_table.first||' Row last: '||my_table.last); END ;

SET SERVEROUTPUT ON DECLARE TYPE CourseList IS TABLE OF VARCHAR2(20); courses CourseList; BEGIN courses := CourseList ( 'Oracle9i SQL', 'Oracle FUNI', 'Oracle FUN II', 'Tuning', 'Oracle PL/SQL', 'Oracle Form', 'Oracle Report','Oracle 10g'); dbms_output.put_line ('1. '||courses.count||' - '||courses(courses.last)); courses.TRIM(2); dbms_output.put_line ('2. '||courses.count||' - '||courses(courses.last)); courses.DELETE(courses.LAST); dbms_output.put_line ('3. '||courses.count||' - '||courses(courses.last)); courses.TRIM(4); dbms_output.put_line('4. '||courses.count||' - '||courses(courses.last)); END;

Summary In this lesson, you should have learned to: Define and reference PL/SQL variables of composite data types: – PL/SQL records – INDEX BY tables – INDEX BY table of records Define a PL/SQL record by using the %ROWTYPE attribute

Practice 5 Overview This practice covers the following topics: Declaring INDEX BY tables Processing data by using INDEX BY tables Declaring a PL/SQL record Processing data by using a PL/SQL record

Oracle - Program with PL/SQL - Lession 05

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