First, you need to create a compressed tablespace by mentioning FILE_BLOCK_SIZE; you cannot alter the tablespace's FILE_BLOCK_SIZE.
If you wish to create a compressed table, you need to create the table in the general tablespace, where the compression is enabled; moreover KEY_BLOCK_SIZE must be equal to FILE_BLOCK_SIZE/1024. If you do not mention KEY_BLOCK_SIZE, the value will be automatically taken from FILE_BLOCK_SIZE.
You can create multiple compressed general tablespaces with different FILE_BLOCK_SIZE values and just add the tables to the desired tablespace:
- Create a general compressed tablespace. You can create one with FILE_BLOCK_SIZE of 8k and other with FILE_BLOCK_SIZE of 4k, and move ...