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分类： oracle
2008-03-13 18:55:58
今天问了一个非常愚蠢的问题，自己学习oracle已经快2年多了，既然还问人家：
objd, dba, slot是什么？干什么用的？
说明自己没有真正的明白。 写上，找到后给补详细些。
============================
objd:
is assigned to each data object, such as table or index when it is created, and it is unique within the database.
objd:
刚开始的时候表的objn和objd是一样，每次truncate table后objd的值将会逐渐增加。视图的objd值为0。
-----------
data block address (dba)：
the dba (here: not the database administrator but the data block address) uniquely identifies a database block in the database.
behind such a database block address is a datafile number and the block number within that database file.
the datafile number can be found with dbms_utility.data_block_address_file. the block number within this file can be found with dbms_utility.data_block_address_block. a database block address can be constructed from a datafile number and a block number with make_data_block_address.
-----------
slot：
dbms_rowid can be used to convert rowids into a
file id (rowid_relative_fno)
block number (rowid_block_number)
slot number in block (rowid_row_number)
objd, dba, slot是什么？干什么用的？
说明自己没有真正的明白。 写上，找到后给补详细些。
============================
objd:
is assigned to each data object, such as table or index when it is created, and it is unique within the database.
objd:
刚开始的时候表的objn和objd是一样，每次truncate table后objd的值将会逐渐增加。视图的objd值为0。
-----------
data block address (dba)：
the dba (here: not the database administrator but the data block address) uniquely identifies a database block in the database.
behind such a database block address is a datafile number and the block number within that database file.
the datafile number can be found with dbms_utility.data_block_address_file. the block number within this file can be found with dbms_utility.data_block_address_block. a database block address can be constructed from a datafile number and a block number with make_data_block_address.
-----------
slot：
dbms_rowid can be used to convert rowids into a
file id (rowid_relative_fno)
block number (rowid_block_number)
slot number in block (rowid_row_number)
给主人留下些什么吧！~~