表信息

select * from dba_unused_col_tabs; 使用 UNUSED 选项 ALTER TABLE orders SET UNUSED COLUMN comments CASCADE CONSTRAINTS; ? 删除未占用的列 ALTER TABLE orders DROP UNUSED COLUMNS CHECKPOINT 1000; ? 将列标记为未占用 ? 继续删除列操作 ALTER TABLE orders DROP COLUMNS CONTINUE CHECKPOINT 1000; 检索表信息 DBA_OBJECTS OWNER OBJECT_NAME OBJECT_ID DATA_OBJECT_ID CREATED DBA_SEGMENTS OWNER SEGMENT_NAME TABLESPACE_NAME HEADER_FILE HEADER_BLOCK DBA_TABLES OWNER TABLE_NAME PCT_FREE PCT_USED INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS PCT_INCREASE CACHE BLOCKS EMPTY_BLOCKS CHAIN_CNT TEMPORARY DURATION 有关表的信息可从数据字典中获取若要获取 SUMMIT 拥有的所有表的数据对 象编号和表头位置请使用下面的查询 SELECT t.table_name, o.data_object_id, s.header_file, s.header_block FROM dba_tables t, dba_objects o, dba_segments s WHERE t.owner=o.owner AND t.table_name=o.object_name AND t.owner=s.owner AND t.table_name=s.segment_name AND t.owner='TIANJIN';