Learning Objective

• That the relational database model offers a logical view of data
  • relational model的基本零件：relations
  • relations由rows (tuples)跟columns (attributes)組成
  • 就把relational DBMS中的relation想像成一個table，例如：學生，而有關學生的信息(tuples, attributes)都儲存在這個table中
• About relational 1.database operators, the 2.data dictionary, and the 3.system catalog
  • data redundancy怎麼處理
  • indexing為什麼重要

<aside> 📻 在資料庫中，relation代表一個表格，而relationship代表表格之間的關係。在關聯式資料庫中，通常會建立多個表格並建立它們之間的關聯，以實現有效的數據管理和操作。

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A Logical View of Data

• Relational database model enables logical representation of the data and its relationships
• Logical simplicity yields simple and effective database design methodologies
• Facilitated by the creation of data relationships based on a logical construct called a relation

STUDENT Table Attribute Values

這邊的foreign key會對照到其他table中相同的foreign key，找到資料。途中紅框。

Keys

• Consist of one or more attributes that determine other attributes
• Used to:
  • Ensure that each row in a table is uniquely identifiable
  • Establish relationships among tables and to ensure the integrity of the data
• Primary key (PK): Attribute or combination of attributes that uniquely identifies any given row

***Determination & Dependencies：***這邊所講的這兩個東西，都是建立在某個table中的relation。