第一正規化

建立 PostgreSQL 資料庫

Darryl Reeves

Industry Assistant Professor, New York University

範例：維護學生紀錄

CREATE TABLE student (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50) NOT NULL,
    courses VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

更新錯誤
插入錯誤
刪除錯誤

範例：更新後的重複資料

id	name	courses	home_room
122	Susan Roth	Algebra I, Physics, Spanish II	101
413	Robert Cruz	History, Geometry, Biology	204
613	Thomas Wright	English III, Chemistry, Algebra II	102

範例：更新後的重複資料

id	name	courses	home_room
122	Susan Roth	Algebra I, Chemistry, Spanish II	101
413	Robert Cruz	History, Geometry, Biology	204
613	Thomas Wright	English III, Chemistry, Algebra II	102

範例：更新後的重複資料

id	name	courses	home_room
122	Susan Roth	Algebra I, Chemistry, Spanish II, Chemistry	101
413	Robert Cruz	History, Geometry, Biology	204
613	Thomas Wright	English III, Chemistry, Algebra II	102

範例：有欄位限制的插入

CREATE TABLE student (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50) NOT NULL,
    courses VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

id	name	courses	home_room
122	Susan Roth	Algebra I, Physics, Spanish II	101
413	Robert Cruz	History, Geometry, Biology	204
613	Thomas Wright	English III, Chemistry, Algebra II	102

範例：有欄位限制的插入

CREATE TABLE student (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50) NOT NULL,
    courses VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

id	name	courses	home_room
122	Susan Roth	Algebra I, Physics, Spanish II	101
413	Robert Cruz	History, Geometry, Biology, French Literature	204
613	Thomas Wright	English III, Chemistry, Algebra II	102

範例：刪除紀錄影響資料完整性

id	name	courses	home_room
122	Susan Roth	Algebra I, Physics, Spanish II	101
413	Robert Cruz	History, Geometry, Biology	204
613	Thomas Wright	English III, Chemistry, Algebra II	102

範例：刪除紀錄影響資料完整性

id	name	courses	home_room
122	Susan Roth	Algebra I, Physics, Spanish II	101
413	Robert Cruz	History, Geometry, Biology	204
613	Thomas Wright	???	102

滿足第一正規化（1NF）

1NF 要求：
- 欄位值必須是原子值

範例：符合 1NF 的 student 資料表

CREATE TABLE student (
    id SERIAL PRIMARY KEY,
    name VARCHAR(50) NOT NULL,
    courses VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

範例：符合 1NF 的 student 資料表

CREATE TABLE student (
    id INTEGER,
    name VARCHAR(50) NOT NULL,
    courses VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

範例：符合 1NF 的 student 資料表

CREATE TABLE student (
    id INTEGER,
    name VARCHAR(50) NOT NULL,
    course VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

範例：符合 1NF 的 student 資料表

id	name	course	home_room
122	Susan Roth	Algebra I	101
122	Susan Roth	Physics	101
122	Susan Roth	Spanish II	101
413	Robert Cruz	History	204
413	Robert Cruz	Geometry	204
413	Robert Cruz	Biology	204

範例：符合 1NF 的 student 資料表

CREATE TABLE student (
    id INTEGER,
    name VARCHAR(50) NOT NULL,
    course VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

範例：符合 1NF 的 student 資料表

CREATE TABLE student (
    student_id INTEGER,
    first_name VARCHAR(50) NOT NULL,
    last_name VARCHAR(50) NOT NULL,
    course VARCHAR(50) NOT NULL,
    home_room SMALLINT NOT NULL
);

範例：符合 1NF 的 student 資料表

id	first_name	last_name	course	home_room
122	Susan	Roth	Algebra I	101
122	Susan	Roth	Physics	101
122	Susan	Roth	Spanish II	101
413	Robert	Cruz	History	204
413	Robert	Cruz	Geometry	204
413	Robert	Cruz	Biology	204

一起來練習吧！

建立 PostgreSQL 資料庫