How Views are Stored (175)

Unlike a table, a view is not allocated any storage space, nor does a view actually
contain data. Rather, a view is defined by a query that extracts or derives data from the
tables that the view references. These tables are called base tables. Base tables can in
turn be actual tables or can be views themselves (including materialized views).
Because a view is based on other objects, a view requires no storage other than storage
for the definition of the view (the stored query) in the data dictionary.

檢視如何儲存
1. 檢視不佔用任何儲存空間 , 不包含實際的資料
2. 檢視從他引用的基表中查詢資料
3. 基表既可以是表，也可以是檢視(包括物化檢視)
4. 檢視只在資料字典中儲存了檢視的定義

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