20140524 Database Lesson Notes

1, you can specify tablespace and storage rules and allocate free table space when creating a table Pctfree

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create table tablename tablespace tsname   storage()pctfree 10(预留大小）, pctused（有多大空间时允许新数据今日）

　　

2, reorganization and reconstruction of database

Reorganization: Reduce fragmentation, improve performance, import and export on the line

Refactoring: Design block size,

One IO time fixed, one IO read a block, first design block size, calculate table space based on table size

The segment contains a series of areas, the region is an integer multiple of the block, the storage scheme of the segment is mainly determined by the initial region, the laundry song area, and the regional growth rate, the maximum minimum area

3, the database supports hot backup, the hot backup is based on the table space