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Mutex
之前也整理过一篇文章来说明Oracle Lock的，参考： 锁 死锁 阻塞 Latch 等待 详解 http://blog.csdn.net/tianlesoftware/archive/2010/08/19/5822674.aspx ...
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Overview of LOBs
Overview of LOBsThe large object (LOB) data types enable you to store and manipulate large blocks of unstructured data in binary or character format. LOBs provide efficient, random, piece-wise access to the data.Internal LOBsAn internal LOB stores data in the database itself rather...
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PL/SQL Subprograms and Packages
一Advantagesof PL/SQL SubprogramsAs explained in"Introduction to Server-Side Programming", server-side programminghas many advantages over client-side programming. PL/SQL subprograms provide the following advantages: 1.Improved performance &nb...
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Understanding Oracle OLAP Dimensions And Cubes
A reader asks:"I am new to OLAP and Oracle OLAP and I have a question. I have an Oracle 10g Database with relational tables in it. I want to create dimensions and cubes from that data. Do I nee...
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Materialized Views
Materialized Views in OracleA materialized view, or snapshot as they were previously known, is a table segment whose contents are periodically refreshed based on a query, either against a local or remote table. Using materialized views against remote tables is the simplest way to achieve re...
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Materialized Views 物化视图 －基础篇
Materialized Views 物化视图 －基础篇我相信对于了解数据仓库的朋友来说，物化视图并不陌生。但网上搜了下关于这方面的介绍相对来说还比较少，在此把自己的学习心得和大家分享。1. 数据仓库和物化视图的关系 对于典型的数据仓库来说，基于每月、每周、每天的大量数据流从一个或多...
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Partitions
Overview of PartitionsPartitioning enables you to decompose very large tables and indexes into smaller and more manageable pieces called partitions. Each partition is an independent object with its own name and optionally its own storage characteristics. 分区能将大的表或索引划分为更小的部分...
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Bitmap Indexes
Bitmap IndexesIn a bitmap index, the database stores a bitmap for each index key. In a conventional B-tree index, one index entry points to a single row. In a bitmap index, each index key stores pointers to multiple rows.Bitmap indexes are primarily designed for data warehousing or environments ...
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Oracle 索引 详解
一．索引介绍 1.1 索引的创建语法： CREATE UNIUQE | BITMAP INDEX . ON . ( |&n...
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Hash Cluster
About Hash ClustersOracle Database uses a hash function to generate a distribution of numeric values, called hash values, that are based on specific cluster key values. The key of a hash cluster, like the key of an index cluster, can be a single column or composite key (multiple column key). To fi...
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Indexex Cluster
Overview of Indexed ClustersAn indexed cluster is a table cluster that uses an index to locate data. The cluster index is a B-tree index on the cluster key. A cluster index must be created before any rows can be inserted into clustered tables.CREATE CLUSTER employees_departments_cluster &...
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Cluster Table
Overview of Table ClustersA table cluster is a group of tables that share common columns and store related data in the same blocks. When tables are clustered, a single data block can contain rows from multiple tables. For example, a block can store rows from both the employees and departments tabl...
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Advanced Compression
Oracle Advanced Compression The Oracle Database 11g Advanced Compression Option introduces a comprehensive set of compression capabilities to help customers maximize resource utilizat...
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Compression One
Table Compression The database can use table compression to reduce the amount of storage required for the table. Compression saves disk space, reduces memory use in the database buffer cache, and in some cases speeds query execution. Table compression is transparent to database applications. 数据...
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Compression Two
As your database grows in size, consider using table compression. Compression saves disk space, reduces memory use in the database buffer cache, and can significantly speed query execution during reads. Compression has a cost in CPU overhead for data loading and DML. However, this cost might be off...
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rowid
Oracle的rowid Oracle中的ROWID是数据的物理...
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Oracle10g之传输表空间详解
可传输表空间概述 Oracle 的可传输表空间特性通过将 元数据和数据文件 简单地从一个数据库移动到另一个数据库，提供在数据库之间有效移动大数据的一种简易方法。代替重新创建对象，可移植表空间可以让毫不费力地移动大对象，而所花费的时间是你手动创建这些对象的时间。可移植表空间包括将属于源数据库的...
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探索数据字典,提高自学习Oracle能力
我们知道Oracle通过数据字典来管理和展现数据库信息，这些信息至关重要。正确理解这部分内容有助于加强我们的oracle学习能力。接下来我们介绍一下怎样通过数据库本身来学习研究数据库。首先，Oracle的字典表和视图基本上可以分为三个层次。1.X$表这一部分表是Oracle数据库的运行基础，在数据库启动时由Orac...
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EXP/IMP简单使用
一，导出(EXP)1.1给予权限执行imp/exp的用户至少有create session权限，session权限包含在connect角色中直接赋予connect权限给指定用户就行；赋予exp_full_database角色可以导出其它schema的表导入则赋予imp_full_da...
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flashback使用
flashback是从oracle9i开始实现的一种恢复功能，完善在10g。10g中利用recyclebin和flashback query功能可以快速的恢复被误删除的table,也可以flashback database 到某个时间点。一，flashback queryflashback qu...
