1. Select the standard database block size. This is specified at database creation by the DB_BLOCK_SIZE initialization parameter and cannot be changed after the database is created.
The SYSTEM tablespace and most other tablespaces use the standard block size. Additionally, you can specify up to four nonstandard block sizes when creating tablespaces.
注：Oracle中最多只能指定四个非标准block size大小的表空间！这里和DB2不一样，在DB2中没有此类限制，DB2中为PAGESIZE参数，在创建数据库时同样可以指定默认值。