How Does oracle extract records in physical order? (From itpub)

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X_X Depressed for a long time ...... Registration Date: 2002 Oct From: Fuzhou Number of posts: 458 How to extract records in physical order? RT Select * from tabname and select/* + first_rows */from tabname? Thank you. __________________ I miss you not because I miss you, but because I miss you. The feeling of being lonely is so important, just because you think too deeply! 04-08-13

Qinhuai night month Senior Member Registration Date: 2001 Sep From: Number of posts: 571 What is the physical order? Is the order in the block? Or the time sequence of records? __________________ War brings wealth and wealth brings about the next war 04-08-13

Li2 Senior Member Registration Date: 2002 Feb From: Number of posts: 871 A problem: if it is a parallel query, is the query merging in physical order? __________________ The gentleman is always dry. When I am silent, I feel full; I will speak, Feel empty at the same time 04-08-14

X_X Depressed for a long time ...... Registration Date: 2002 Oct From: Fuzhou Number of posts: 458 Quote: Originally released by Qinhuai night month What is the physical order? Is the order in the block? Or the time sequence of records? It should be the time sequence of record generation In fact, what I want to ask is: is the order of data retrieved by select * From tabname the same? __________________ I miss you not because I miss you, but because I miss you. The feeling of being lonely is so important, just because you think too deeply! 04-08-14 :53

Qinhuai night month Senior Member Registration Date: 2001 Sep From: Number of posts: 571 Quote: Initially released by X_X It should be the time sequence of record generation In fact, what I want to ask is: is the order of data retrieved by select * from tabname the same? I feel that the select * from table is always scanned by block (it has not been verified by experiments, but it should be so in terms of efficiency ), the records inserted later may use the space left by the previous delete, so this is not necessarily in chronological order. In fact, relational databases emphasize physical independence. All operations only ensure the logic layer. If you want to extract rows in chronological order, you 'd better add a column to record the generation time of rows. __________________ War brings wealth and wealth brings about the next war 04-08-14 13:21

Grassbell Deep discussion area bamboo Registration Date: 2003 Jun From: Beijing, Xiamen Number of posts: 1018 Quote: Originally released by Qinhuai night month I feel that the select * from table is always scanned by block (it has not been verified by experiments, but it should be so in terms of efficiency ), the records inserted later may use the space left by the previous delete, so this is not necessarily in chronological order. In fact, relational databases emphasize physical independence. All operations only ensure the logic layer. If you want to extract rows in chronological order, you 'd better add a column to record the generation time of rows. Select * from table return values: The rows in the same block are read in the order of row dictionary in the block header. Delete and insert again. Later, the row may use the deleted row in the row dictionary position. However, the order between blocks is probably determined by the order in which blocks is arranged in the segment. __________________ Donny's Email Instead of your own, you can do more research, experiment, and write your own experiences. 04-08-14 16:03

Grassbell Deep discussion area bamboo Registration Date: 2003 Jun From: Beijing, Xiamen Number of posts: 1018 Refer: Http://www.itpub.net/112239.html Http://www.itpub.net/247459.html __________________ Donny's Email Instead of your own, you can do more research, experiment, and write your own experiences. 04-08-14 16: 05

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