MySQL-如何插入具有多对多关系的表 [英] MySQL - How to insert into table that has many-to-many relationship
问题描述
我有一张桌子.每个人都有财产,许多人可能有一定财产.因此,这是一个多对多的关系.这是模式:
I have a table of persons. Each person has a property and many persons may have a certain property. So this is a many-to-many relationship. This is the schema:
CREATE TABLE persons (
person_id int(11) NOT NULL AUTO_INCREMENT,
firstname varchar(30) NOT NULL,
lastname varchar(30) NOT NULL,
PRIMARY KEY (person_id)
);
CREATE TABLE properties (
property_id int(11) NOT NULL AUTO_INCREMENT,
property varchar(254) NOT NULL UNIQUE,
PRIMARY KEY (property_id)
);
CREATE TABLE has_property (
person_id int(11) NOT NULL,
property_id int(11) NOT NULL,
PRIMARY KEY (person_id,property_id),
FOREIGN KEY (person_id) REFERENCES persons (person_id),
FOREIGN KEY (property_id) REFERENCES properties (property_id)
);
现在让我说我想将此人插入数据库:
Now lets say i want to insert to the database this person:
- 名字:约翰"
- 姓:'Doe'
- 属性:'property_A','property_B','property_C'
人
+-----------+-----------+----------+
| person_id | firstname | lastname |
+-----------+-----------+----------+
| 1 | John | Doe |
+-----------+-----------+----------+
属性
+-------------+------------+
| property_id | property |
+-------------+------------+
| 1 | property_A |
| 2 | property_B |
| 3 | property_C |
+-------------+------------+
具有财产
+-----------+-------------+
| person_id | property_id |
+-----------+-------------+
| 1 | 1 |
| 1 | 2 |
| 1 | 3 |
+-----------+-------------+
到目前为止,我认为最好的事情是在人员表中进行常规插入:
So far the best thing i have thought is to do a regular insert in the persons table:
INSERT INTO persons (firstname,lastname) VALUES ('John','Doe');
,然后进行选择以查找我刚刚插入的人的ID
and then do a select to find the id of the person i just inserted
SELECT person_id FROM persons WHERE firstname='John' AND lastname='Doe';
为了插入其他两个表(因为我需要知道person_id). 但是我认为必须有更好的方法,不是吗?
in order to insert into the other two tables (because i need to know the person_id). But i think there must be a better way, isn't it?
推荐答案
这就是我最终要做的事情.我希望它能对某人有所帮助.
Here is what i ended up doing. I hope it helps someone.
INSERT INTO persons (firstname,lastname) VALUES ('John','Doe');
SET @person_id = LAST_INSERT_ID();
INSERT IGNORE INTO properties (property) VALUES ('property_A');
SET @property_id = LAST_INSERT_ID();
INSERT INTO has_property (person_id,property_id) VALUES(@person_id, @property_id);
INSERT IGNORE INTO properties (property) VALUES ('property_B');
SET @property_id = LAST_INSERT_ID();
INSERT INTO has_property (person_id,property_id) VALUES(@person_id, @property_id);
INSERT IGNORE INTO properties (property) VALUES ('property_C');
SET @property_id = LAST_INSERT_ID();
INSERT INTO has_property (person_id,property_id) VALUES(@person_id, @property_id);
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