Design method of activity participation table for grocery shopping system in MySQL

The activity participation table design method of the food shopping system in MySQL

Introduction:
As online shopping becomes more and more popular, the food shopping system has also become a part of people’s lives part of. In the grocery shopping system, the activity participation form plays an important role. This article will introduce the design method of the activity participation table of the grocery shopping system in MySQL and give specific code examples.

Design method of activity participation table:
In the grocery shopping system, the activity participation table is used to record information about user participation in activities, including user number (userId), activity number (activityId), participation time ( joinTime) and other fields. There is a correlation relationship between the activity participation table, the user table and the activity table. You can perform correlation queries with the user table and activity table through the user number and activity number.

Based on the above requirements, we can design the structure of the following activity participation table:

CREATE TABLE activity_participation (
id int(11) NOT NULL AUTO_INCREMENT,
user_id int(11) NOT NULL,
activity_id int(11) NOT NULL,
join_time datetime NOT NULL,
PRIMARY KEY (id),
INDEX idx_user_id (user_id),
INDEX idx_activity_id ( activity_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

In the activity participation table, id is the unique identifier of the activity participation record, user_id is the user number, and activity_id is the activity number. , join_time is the participation time. Use the AUTO_INCREMENT keyword to automatically generate a unique event participation record id for the id field. In order to improve query efficiency, indexes (INDEX keyword) are added to the user_id and activity_id fields.

Code example:

1. Insert activity participation record

INSERT INTO activity_participation (user_id, activity_id, join_time) VALUES (1, 1, NOW());

The above example will insert a user ID of 1, activity ID of 1, and participation time into the activity participation table. Record activity participation for the current time.

2. Query user participation activity information

SELECT user.username, activity.title, activity.start_time, activity.end_time
FROM activity_participation
LEFT JOIN user ON activity_participation.user_id = user.id
LEFT JOIN activity ON activity_participation.activity_id = activity.id
WHERE user_id = 1;

The above example obtains the activity information of the user with id 1 through the correlation query between the activity participation table, the user table and the activity table, and returns the user name, activity title, activity start time and activity end time.

Summary:
In the grocery shopping system, the activity participation form is a very important part. This article introduces the design method of the activity participation table of the grocery shopping system in MySQL, and gives specific code examples. Through reasonable design and coding, event participation information can be better managed and queried, and the user experience of the grocery shopping system can be improved.

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