計算機概論筆記-Database Fundamentals

CH9-1 Database Fundamentals

1. database : a collection of data that is multidimensional in the sense that internal links between its entries make the information accessible from a variety of perspectives.

代表一組多種資料的結合,而資料彼此間都有特殊關聯,所以使用者可以用不同的角度來使用。

 

2. flat file : It is a one-dimensional storage system , meaning that it presents its information from a single point of view.

         只用一種角度去看待某ㄧ資料,然後產生的一維資料儲存系統。

 

3. The ability to control access to the information in the database is as important as the ability to share it.

資料存取的控制能力和資源分享的能力,對於資料庫來講,兩者是很重要的。

 

4. Schema : 總覽

(1) It is a description of the entire database structure that is used by database to matain the database.

“Schema”表示資料庫軟體維護資料庫,所需要的一個整體資料庫結構的描述。

 

5.Subschema : 個覽

(1) It is a description of only that portion of the database pertinent to a particular user`s needs.

針對個別使用者的需求在資料庫的部份描述。

 

6. DBMS : Database Management System

(1) The actual manipulation of the database is accomplish by another software layer.

資料庫的實際處理其實是由另一層的軟體去處理完成。

 

7. Distributed Database:

(1) The database is stored on multiple computers or scattered among many machines in network.

資料庫式儲存在多個電腦上,或者分散在網路中多個機器。

 

8. Data Independence:

(1) The ability to change the organization of a database without changing the application software that uses it.

在改變資料結構時,不必改變應用程式的能力。

9.Database model:

(1) This conceptual view of database.

資料庫管理的各種常規,將概念觀點的命令,轉換成實際資料庫儲存系統的動作。

(2) Relational database model.

 

(3) Object-Oriented database model.