表信息

select * from dba_unused_col_tabs;使用 UNUSED 选项ALTER TABLE ordersSET UNUSED COLUMN commentsCASCADE CONSTRAINTS;? 删除未占用的列ALTER TABLE ordersDROP UNUSED COLUMNS CHECKPOINT 1000;? 将列标记为未占用? 继续删除列操作ALTER TABLE ordersDROP COLUMNS CONTINUE CHECKPOINT 1000;检索表信息DBA_OBJECTSOWNEROBJECT_NAMEOBJECT_IDDATA_OBJECT_IDCREATEDDBA_SEGMENTSOWNERSEGMENT_NAMETABLESPACE_NAMEHEADER_FILEHEADER_BLOCKDBA_TABLESOWNERTABLE_NAMEPCT_FREEPCT_USEDINITIAL_EXTENTNEXT_EXTENTMIN_EXTENTSMAX_EXTENTSPCT_INCREASECACHEBLOCKSEMPTY_BLOCKSCHAIN_CNTTEMPORARYDURATION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_nameAND t.owner='TIANJIN';