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《Pro Oracle SQL》Chapter 3 -- 3.3.2 Sort-Merge Joins

Sort-Merge Joins    排序-合并连接       (page 114)    Sort-merge joins read the two tables to be joined independently, sorts the rows from each table (but only those rows that meet the conditions for the ...
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caohong286 评论(0) 有1025人浏览 2012-03-27 22:07

《Pro Oracle SQL》Chapter 3 -- 3.3.1 Nested Loops Joins

Nested Loops Joins  嵌套循环连接       (page 111)     Nested loops joins use each row of the query result reached through one access operation to drive into another table.  These joins are typically m ...
Pro Oracle SQLOracleSQLApressDBA 
caohong286 评论(0) 有1058人浏览 2012-03-25 18:12

《Pro Oracle SQL》Chapter 3 -- 3.3 Join Methods

Join Methods  连接方法   (page 110)     If there are multiple tables in your query, after the optimizer determines the access methods most appropriate for each of the tables, the next st ...
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caohong286 评论(0) 有1036人浏览 2012-03-24 15:51

《Pro Oracle SQL》Chapter3--3.2.7 Index Fast Full Scan

Index Fast Full Scan  索引快速全扫描    (page 109)     An index fast full scan is more like a full table scan than like other index scan types.  When an index fast full scan operation is chosen, all the ...
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caohong286 评论(0) 有1544人浏览 2012-03-24 01:09

《Pro Oracle SQL》Chapter3--3.2.6 Index Skip Scan

Index Skip Scan    索引跳跃扫描     (page 107)     An index skip scan is chosen when the predicate contains a condition on a non-leading column in an index and the leading columns are fairly distin ...
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caohong286 评论(0) 有1158人浏览 2012-03-23 00:57

《Pro Oracle SQL》Chapter 3--3.2.5 Index Full Scan

Index Full Scan  索引全扫描   (page 103)     An index full scan is chosen under several conditions including: when there is no predicate but the column list can be satisfied through an index on a colu ...
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caohong286 评论(0) 有957人浏览 2012-03-22 05:08

oracle基础

oracle 查看 用户，用户权限，用户表空间，用户默认表空间 1.查看用户和默认表空间的关系。      select   username,default_tablespace   from   dba_users; 2.查看当前用户的表： select  table_name from  user_tables; 3.查看所有用户的表名： select table_nam ...
oracletablespacedba 
lilin530 评论(0) 有833人浏览 2012-03-20 14:37

《Pro Oracle SQL》Chapter3--3.2.4 Index range scan

Index range scan    索引范围扫描    (page 101)     An index range scan is chosen when a predicate contains a condition that will return a range of data.   The index can be unique or non-unique as it i ...
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caohong286 评论(0) 有1050人浏览 2012-03-20 00:10

《Pro Oracle SQL》Chapter3--3.2.3 Index Unique Scan

Index Unique Scan    索引唯一扫描     (page 78)     An index unique scan is chosen when a predicate contains a condition using a column defined with a UNIQUE or  PRIMARY KEY  ind ...
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caohong286 评论(0) 有992人浏览 2012-03-19 05:26

《Pro Oracle SQL》Chapter3--3.2.2 Index Scan Types

Index Scan Types  索引扫描类型      (page 97)     There are several different types of index scans but each share some common ground in how they must traverse the index structure to a ...
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caohong286 评论(0) 有1039人浏览 2012-03-17 23:34

《Pro Oracle SQL》Chapter3--3.2 Index Scan Access Methods--3.2.1 Index Structure

Index Scan Access Methods      索引扫描访问方法   (page 95)     If you have a book about U.S. Presidents and want to find information on Jimmy Carter, you could start on the first page and visually s ...
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caohong286 评论(0) 有970人浏览 2012-03-15 20:04

《Pro Oracle SQL》Chapter3--3.1.4 Full Scans and the Highwater Mark

Full Scans and the Highwater Mark    全扫描和高水标识     A final point of note regarding full table scans is that as the multiblock read calls for the scan are made, Oracle will r ...
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caohong286 评论(0) 有967人浏览 2012-03-14 20:49

《Pro Oracle SQL》Chapter3--3.1 Full Scan Access Methods 之二

Full Scans and Throwaway  全扫描和“抛弃”     Always remember that whether or not a full scan will be an effective choice depends on the number of blocks that will need to be read as much as on how man ...
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caohong286 评论(0) 有943人浏览 2012-03-11 23:14

《Pro Oracle SQL》Chapter3--3.1Full Scan Access Methods之一

Chapter3  Access and Join Methods 访问和连接方法 Karen Morton     (page 83)     The optimizer must determine how to access the data your SQL statements require. You formulate your statement and the opti ...
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caohong286 评论(0) 有946人浏览 2012-03-10 18:01

《Pro Oracle SQL》Chapter8--8.9 Advanced topics

Advanced topics     高级主题      (page 268)     A few advanced topics about the analytic functions are worthy of discussion. I will discuss topics such as dynamic analytic statements ...
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caohong286 评论(0) 有1104人浏览 2012-03-05 21:41

《Pro Oracle SQL》Chapter8--8.8 Performance Tuning

Performance Tuning     性能调优      (page 266)     Analytic functions are very useful in tuning complex SQL statements. Inter-row referencing, aggregation at multiple levels, and nth-row access are a ...
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caohong286 评论(0) 有707人浏览 2012-03-02 23:11

《Pro Oracle SQL》Chapter 8 -- 8.7 Other Analytic Functions 之三

NTILE       （page 263）     The  NTILE  function divides an ordered set of rows in a data partition, groups them in to buckets , and assigns a unique group number to each group. This functio ...
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caohong286 评论(0) 有1021人浏览 2012-02-29 22:09

《Pro Oracle SQL》Chapter 8 -- 8.7 Other Analytic Functions 之二

Ratio_to_report         (page 259)     The analytic function ratio_to_report calculates the ratio of a value to the sum of values in the data partition. If the partitioning clause ...
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caohong286 评论(0) 有880人浏览 2012-02-26 22:14

《Pro Oracle SQL》Chapter 8 -- 8.7 Other Analytic Functions 之一

Other Analytic Functions    (page254)     Oracle Database implements a great many other analytic functions. Some of those more commonly used are described in the following subsections. The fun ...
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caohong286 评论(0) 有1058人浏览 2012-02-26 14:35

《Pro Oracle SQL》Chapter 8--8.6 First_ value & Last_value

First_value & Last_value      (page 252)      First_value and last_value functions are useful in calculating the maximum and minimum values in an orered result set. The first_v ...
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caohong286 评论(0) 有903人浏览 2012-02-21 23:52

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