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oracle metadate 元数据

Jun 07, 2016 pm 03:51 PM
oracle data express

METADATA表示元数据的意思,oracle系统和每个对象都有自己的元数据 元数据就是关于数据的数据 元数据,准确说是描述数据的数据。 元数据是库中库,描述的是数据库的相关信息,如对象的属性之类的大概这个意思 每个Oracle数据库中包括一个被称为“元数据”的集

METADATA表示元数据的意思,oracle系统和每个对象都有自己的元数据

元数据就是关于数据的数据
元数据,准确说是描述数据的数据。
元数据是库中库,描述的是数据库的相关信息,如对象的属性之类的大概这个意思
每个Oracle数据库中包括一个被称为“元数据”的集合,或者说包含用来描述数据库有关数据结构的数据。
包含这些元数据的表和视图称为Oracle数据字典

比如说有一个表A,表A中都是数据,而描述表A的数据,就是元数据。像表A有哪些列,每列的宽度、类型,哪些列上有什么样的索引,等等。
Oracle的元数据都存放在数据字典中。

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