Mega Code Archive

The EXISTS Table Attribute

SQL> SQL> SQL> CREATE TABLE lecturer ( 2 id NUMBER(5) PRIMARY KEY, 3 first_name VARCHAR2(20), 4 last_name VARCHAR2(20), 5 major VARCHAR2(30), 6 current_credits NUMBER(3) 7 ); Table created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10001, 'Scott', 'Lawson','Computer Science', 11); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major, current_credits) 2 VALUES (10002, 'Mar', 'Wells','History', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10003, 'Jone', 'Bliss','Computer Science', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10004, 'Man', 'Kyte','Economics', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10005, 'Pat', 'Poll','History', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10006, 'Tim', 'Viper','History', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10007, 'Barbara', 'Blues','Economics', 7); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10008, 'David', 'Large','Music', 4); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10009, 'Chris', 'Elegant','Nutrition', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10010, 'Rose', 'Bond','Music', 7); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10011, 'Rita', 'Johnson','Nutrition', 8); 1 row created. SQL> SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits) 2 VALUES (10012, 'Sharon', 'Clear','Computer Science', 3); 1 row created. SQL> SQL> CREATE TABLE MyTable ( 2 num_col NUMBER, 3 char_col VARCHAR2(60) 4 ); Table created. SQL> SQL> DECLARE 2 TYPE t_FirstNameTable IS TABLE OF lecturer.first_name%TYPE 3 INDEX BY BINARY_INTEGER; 4 FirstNames t_FirstNameTable; 5 BEGIN 6 FirstNames(1) := 'Scott'; 7 FirstNames(3) := 'Joanne'; 8 9 IF FirstNames.EXISTS(1) THEN 10 INSERT INTO MyTable (char_col) VALUES 11 ('Row 1 exists!'); 12 ELSE 13 INSERT INTO MyTable (char_col) VALUES 14 ('Row 1 doesn''t exist!'); 15 END IF; 16 IF FirstNames.EXISTS(2) THEN 17 INSERT INTO MyTable (char_col) VALUES 18 ('Row 2 exists!'); 19 ELSE 20 INSERT INTO MyTable (char_col) VALUES 21 ('Row 2 does n''t exist!'); 22 END IF; 23 END; 24 / PL/SQL procedure successfully completed. SQL> SQL> select * from MyTable; NUM_COL CHAR_COL ---------- ------------------------------------------------------------ Row 1 exists! Row 2 does n't exist! SQL> SQL> drop table lecturer; Table dropped. SQL> SQL> drop table MyTable; Table dropped.