这是在 3NF 中吗？

Question

这是在 3NF 中吗？

mysql show tables;
+--------------------+
| Tables_in_hospital |
+--------------------+
| address            |
| bed                |
| department         |
| hospital_number    |
| phone_number       |
| region             |
| type               |
+--------------------+

mysql desc hospital_number;  //PRI key = Hospital_Number

+-----------------+-------------+------+-----+---------+-------+
| Field           | Type        | Null | Key | Default | Extra |
+-----------------+-------------+------+-----+---------+-------+
| name            | varchar(64) | NO   |     | NULL    |       |
| Hospital_Number | int(11)     | NO   | PRI | NULL    |       |
+-----------------+-------------+------+-----+---------+-------+

mysql desc address; //PRI key = Address, FOR key = Hospital_number

+-----------------+--------------+------+-----+---------+-------+
| Field           | Type         | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+-------+
| Address         | varchar(128) | NO   | PRI | NULL    |       |
| Latitude        | double       | NO   |     | NULL    |       |
| Longitude       | double       | NO   |     | NULL    |       |
| Postcode        | varchar(32)  | NO   |     | NULL    |       |
| Hospital_Number | int(11)      | NO   | MUL | NULL    |       |
+-----------------+--------------+------+-----+---------+-------+

mysql desc department; //PRI key = Hospital_number + Department, 
                        //FOR key = Hospital_number

+-----------------+-------------+------+-----+---------+-------+
| Field           | Type        | Null | Key | Default | Extra |
+-----------------+-------------+------+-----+---------+-------+
| Hospital_Number | int(11)     | NO   | PRI | NULL    |       |
| Department      | varchar(64) | NO   | PRI | NULL    |       |
+-----------------+-------------+------+-----+---------+-------+

mysql desc bed; //PRI key = Hospital_number + Bed, 
                 //FOR key = Hospital_number
+-----------------+---------+------+-----+---------+-------+
| Field           | Type    | Null | Key | Default | Extra |
+-----------------+---------+------+-----+---------+-------+
| Hospital_Number | int(11) | NO   | PRI | NULL    |       |
| Bed             | int(11) | NO   | PRI | NULL    |       |
+-----------------+---------+------+-----+---------+-------+

mysql desc phone_number; //PRI key = Hospital_number + Phone_number, 
                          //FOR key = Hospital_number
+-----------------+-------------+------+-----+---------+-------+
| Field           | Type        | Null | Key | Default | Extra |
+-----------------+-------------+------+-----+---------+-------+
| Hospital_Number | int(11)     | NO   | PRI | NULL    |       |
| Phone_Number    | varchar(64) | NO   | PRI | NULL    |       |
+-----------------+-------------+------+-----+---------+-------+

mysql desc region; //PRI key = Hospital_number + region, 
                    //FOR key = Hospital_number
+-----------------+-------------+------+-----+---------+-------+
| Field           | Type        | Null | Key | Default | Extra |
+-----------------+-------------+------+-----+---------+-------+
| Hospital_Number | int(11)     | NO   | PRI | NULL    |       |
| Region          | varchar(12) | NO   | PRI | NULL    |       |
+-----------------+-------------+------+-----+---------+-------+

mysql desc type; //PRI key = Hospital_number + type, 
                  //FOR key = Hospital_number
+-----------------+-------------+------+-----+---------+-------+
| Field           | Type        | Null | Key | Default | Extra |
+-----------------+-------------+------+-----+---------+-------+
| Hospital_Number | int(11)     | NO   | PRI | NULL    |       |
| Type            | varchar(12) | NO   | PRI | NULL    |       |
+-----------------+-------------+------+-----+---------+-------+

第一次用MySQL做数据库table，不知道是否满足3NF。 1 NF 对将部门 table 从医院 table 分开感到满意。我认为 2 NF、3 NF 令人满意，但我不确定。请检查我的数据库我的表格有什么错误的部分？

Answer 1

我所说的医院和地区（或类型）之间的多对多关系过于复杂：给定的医院不太可能与多个地区相关联（至少在您的模型中不是；医院可以存在多个区域）。因此，我们将采用更简单的一对多关系。您的模型中的问题仍然存在，您可能在同一地区拥有多家医院，如果您决定更改该地区的名称，您将需要更新多行（与 type [=26 相同的故事=]):

使用 tables hospital_number（顺便说一句，我可能只是命名为 hospital）和 region 作为示例（您可以概括这个至 table type):

CREATE TABLE `region` (
  `Region_Number` int(11) NOT NULL AUTO_INCREMENT,
  `Region` varchar(12) NOT NULL,
  PRIMARY KEY (`Region_Number`)
) ENGINE=InnoDB;


CREATE TABLE `hospital_number` (
  `name` varchar(64) NOT NULL,
  `Hospital_Number` int(11) NOT NULL AUTO_INCREMENT,
  `Region_Number` int(11) NOT NULL,
  PRIMARY KEY (`Hospital_Number`),
  CONSTRAINT FOREIGN KEY (`Region_Number`) REFERENCES `region` (`Region_Number`) ON UPDATE CASCADE
) ENGINE=InnoDB;

请注意，在 table region 中，列 Region 不是主键的一部分。

这是在 3NF 中吗？

is this in 3NF?

mysql

sql

3nf

database-normalization