SQL & PL/SQL

I need to maintain history of changes into target table. If there is any update, delete or insert into source table it should be reflected into target table and latest record should be marked as Y for each ID. Attached image for better understanding.
oracle.JPG (70.2 KB)--CREATE SOURCE AND TARGET TABLES
CREATE TABLE SOURCE (ID NUMBER, NAME VARCHAR(20));
CREATE TABLE TARGET(ID NUMBER, NAME VARCHAR(20), ACTIVE_FLAG VARCHAR2(2));
STEP 1 (LOADING SORCE TABLE)
INSERT INTO SOURCE VALUES (1,'AAA');
INSERT INTO SOURCE VALUES (2,'BBB');
SOURCE TABLE
EXPECTED TRAGET TABLE

STEP 2 (INSET AND UPDATE INTO SOURCE TABLE)
INSERT INTO SOURCE VALUES (3,'CCC');
UPDATE TABLE SOURCE
SET NAME = 'ZZZ'
WHERE ID =1;
SOURCE TABLE
EXPECTED TARGET TABLE

It would be great help if someone could help me to generate the code for this.