Oracle SQL Developer

Utilizing the Main Features of PL/SQL7.3.10.2 Using the %TYPE Attribute to Declare VariablesThe %TYPE attribute provides the data type of a variable or table column. This isparticularly useful when declaring variables that will hold values of a table column.For example, suppose you want to declare variables as the same data type as columnsemployee_id and last_name in table employees. To declare variables namedempid and emplname that have the same data type as the table columns, use dotnotation and the %TYPE attribute. See Example 7–11.Example 7–11Using %TYPE With Table ColumnsDECLARE -- declare variables using %TYPE attributeempid employees.employee_id%TYPE; -- employee_id data type is NUMBER(6)emplname employees.last_name%TYPE; -- last_name data type is VARCHAR2(25)BEGINempid := 100301; -- this is OK because it fits in NUMBER(6)-- empid := 3018907; -- this is too large and will cause an overflowemplname := 'Patel'; -- this is OK because it fits in VARCHAR2(25)DBMS_OUTPUT.PUT_LINE('Employee Id: ' || empid); -- display dataDBMS_OUTPUT.PUT_LINE('Employee name: ' || emplname); -- display dataEND;/Declaring variables with %TYPE has two advantages. First, you need not know theexact data type of the table columns. Second, if you change the database definition ofcolumns, such as employee_id or last_name, the data types of empid andemplname in Example 7–11 change accordingly at run time.See Also:%TYPEPL/SQL User's Guide and Reference for information on7.3.11 Using PL/SQL Control StructuresControl structures are the most important PL/SQL extension to SQL. Not only doesPL/SQL let you manipulate Oracle data, it lets you process the data using conditional,iterative, and sequential flow-of-control statements such as IF-THEN-ELSE, CASE,FOR-LOOP, WHILE-LOOP, EXIT-WHEN, and GOTO.7.3.11.1 Conditional Control With IF-THENOften, it is necessary to take alternative actions depending on circumstances. TheIF-THEN statement lets you execute a sequence of statements conditionally. The formsof the statement can be IF-THEN, IF-THEN-ELSE, or IF-THEN-ELSEIF-ELSE. TheIF clause checks a condition, the THEN clause defines what to do if the condition istrue and the ELSE clause defines what to do if the condition is false or null.Example 7–12 shows a simple use of the IF-THEN statement.Example 7–12Using a Simple IF-THEN StatementDECLAREsales NUMBER(8,2) := 10100;quota NUMBER(8,2) := 10000;bonus NUMBER(6,2);emp_id NUMBER(6) := 120; -- use employee 120 for testingBEGINIF sales > (quota + 200) THENbonus := (sales - quota)/4;UPDATE employees SET salary = salary + bonus WHERE employee_id = emp_id;END IF;PL/SQL: Usage Information 7-11