How-to: Oracle Datatypes Data types for Oracle 8 to Oracle 19. Variable length character string having maximum length size bytes. You must specify size. n.b. max is only 32,767 bytes or characters if MAX_STRING_SIZE = EXTENDED Maximum size is: 32,767 bytes or characters if MAX_STRING_SIZE = EXTENDED 4,000 bytes or characters if MAX_STRING_SIZE = STANDARD (MAX_STRING_SIZE = EXTENDED requires Oracle