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X_x long-term depressed ... Registration Date: 2002 OCT From: Fuzhou Posting Quantity: 458
How to extract records in physical order? RtSelect * from tabname and SELECT / * first_ROWS * / from TabName? Thank you _________________, not because of loneliness, think of you, but because you want you to be lonely. The reason why the lonely feels is so heavy, just because it is too deep! 04-08-13 18:24
Qinhuai night moon Senior Member Registration Date: 2001 Sep From: Post Number: 571
What is the physical order? Is it arranged in the block in Block? Or is it recorded? _________________ war brings wealth, wealth brings the next war 04-08-13 22:36
LI2 Advanced Member Registration Date: 2002 Feb From: Post Quantity: 871
A little problem, if it is a parallel query, is it inquiry? 04-08-14 10:16
X_x long-term depressed ... Registration Date: 2002 OCT From: Fuzhou Posting Quantity: 458
Quote:
What is the physical order from Qin Huai night moon? Is it arranged in the block in Block? Or is it recorded?
It should be that the time of the record is actually what I want to ask, select * from tabname is not the same, what is the order? __________________ not thinking of you because loneliness, but because you want you to be lonely. The reason why the lonely feels is so heavy, just because it is too deep! 04-08-14 10:53
Qinhuai night moon Senior Member Registration Date: 2001 Sep From: Post Number: 571
Quote:
Originally published by x_x should be the time order generated by the record. In fact, I want to ask, select * from tabname is not the same, what is the order of order?
I feel that SELECT * from take is a manual scan by block (there is no experimental verification, but it should be seen from the efficiency angle), because the recorded records may be used in the front delete vacation, so this is not necessarily Arrive in time, the relational database emphasizes physical irrelevant, all operations only guarantee the logical layer, if you want to extract lines in time, it is best to add a column to record line generation time _________________ warband Come to wealth, wealth brings the next war 04-08-14 13:21
Grassbell in-depth discussion Zone Zone Registration Date: 2003 Jun From: Beijing, Xiamen Posting Quantity: 1018
Quote:
I initially released by Qin Huai night moon. I feel that select * from table is to scan by Block (there is no experimental verification, but it should be seen from the efficiency angle), because the recorded record may be used in front of Delete vacation, So this is not necessarily to arrange in time, the relational database emphasizes physical irrelevant, all operations only guarantee the logical layer, if you want to extract lines in time, it is best to add a column to record the generation time
SELECT * from a return value: The ROWS in the same block is read in the order of ROW in the row Dictionary of the block header. After Delete, INSERT, the later ROW may use the deleted row in the Row Dictionary location. But the order between Block, I speculate is the order in accordance with Blocks in Segment in Segment. _________________Rmny's email is not his own, more research, more experiments, write the experience, become your own 04-08-14 16: 03grassbell in-depth discussion Zone Zone Registration Date: 2003 Jun From: Beijing, Xiamen Posting quantity: 1018
Complose: http://www.itpub.net/112239.htmlhttp://www.itpub.net/247459.html _________________ Donny's Email is not his own, more research, more experiments, write the experience, become your own 04-08-14 16:05
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