Nodejs realizes unlimited classification

With the development of the Internet, website content has become more complex, and the classification of various data in web pages has become more and more complex. Unlimited classification is an extremely common way of classifying goods, which can deal with complex classification problems in different business scenarios. This article will introduce how to use Nodejs to implement unlimited classification functions.

1. Prerequisite knowledge points

Before learning how to achieve infinite classification, we need to understand the following prerequisite knowledge points:

1. Mysql database

Mysql database is an open source relational database management system. In unlimited classification, we need to use a database to store classification data.

2. Express Framework

Express framework is a rapidly developed web application framework based on the Nodejs platform. It provides some powerful features, such as routing, middleware, template engine, etc., making developing web applications easier and faster.

3. Handwritten sql statements

In order to operate the database, we need to master some basic sql statements, such as query, insert, modify, delete, etc.

2. Definition of infinite classification

Infinite classification is a classification method that divides product data according to hierarchical relationships. For example, in e-commerce, a product may belong to a large category, such as clothing, and within this large category of clothing, there will be many small categories, such as tops, pants, skirts, etc., and these small categories will have more detailed categories. points content.

Therefore, an important feature of infinite classification is that there is a hierarchical relationship between categories, that is, each category may contain sub-categories, and each sub-category can have its own sub-category, and this relationship can continue to extend. to the lowest level of classification.

In addition, an important feature of unlimited classification is that the number of classifications is uncertain. We can add or delete classifications at any time without making extensive adjustments to the hierarchical structure of existing classifications.

3. Design the database structure

Before realizing the unlimited classification function, we need to design a suitable database structure to meet the data storage required for classification. We need to create a table in the database to store classification information. This table needs to contain the following fields:

1. id

This field is the unique identifier of the classification. Can be created using a self-increasing integer type.

2. name

This field is the name of the category. The varchar type can be used to store string type data.

3. parent_id

This field is used to store the parent category ID of the current category. If the current category is a first-level category, parent_id is 0.

4. Create an API interface of unlimited categories

After the database structure is created, we need to use the Nodejs Express framework to create an API interface of unlimited categories. We need to implement the following interfaces:

1. Query all categories

This interface is used to query all categories, and the returned results need to be sorted according to the hierarchical relationship of the categories. The implementation process is as follows:

① Use the database's connection pool or connection operation to connect to the database.

② Use sql statements to query all classified data. The sql statement is as follows:

SELECT * FROM `category` ORDER BY parent_id, id;

This sql statement sorts all categories according to parent_id and id.

③ Return the query results to the front-end display page.

2. Query a single category

This interface is used to query the information of a single category, including the category name, ID, parent category ID, etc. The implementation process is as follows:

① Get the category ID passed in by the front end.

② Use sql statement to query the information of the specified category. The sql statement is as follows:

SELECT * FROM `category` WHERE `id` = ?;

This sql statement is used to query the classification of the specified ID.

③ Return the query results to the front-end display page.

3. Add new category

This interface is used to add a new category. The implementation process is as follows:

① Obtain the classification information passed in by the front end, including the classification name and parent classification ID.

② Use sql statements to insert new classified data. The sql statement is as follows:

INSERT INTO `category` (`name`, `parent_id`) VALUES (?, ?);

This sql statement is used to insert new classified data into the database.

③ Return the insertion result to the front-end display page.

4. Edit Category

This interface is used to edit the information of the specified category. The implementation process is as follows:

① Obtain the classification information passed in by the front end, including the classification name and classification ID.

② Use sql statements to update the data of the specified category. The sql statement is as follows:

UPDATE `category` SET `name` = ? WHERE `id` = ?;

This sql statement is used to update the name of the category with the specified ID.

③ Return the update results to the front-end display page.

5. Delete Category

This interface is used to delete the specified category. The implementation process is as follows:

① Get the category ID passed in by the front end.

② Use sql statement to delete the category with the specified ID. The sql statement is as follows:

DELETE FROM `category` WHERE `id` = ?;

This sql statement is used to delete the category with the specified ID.

③ Return the deletion result to the front-end display page.

5. Implement unlimited classification

By creating the above interface, we have been able to implement basic operations on classified data. However, we also need to implement the core logic of infinite classification in Nodejs.

The implementation process is as follows:

① Use sql statements to query all classified data.

② Process the query results and sort all categories according to hierarchical relationships.

③ Use a recursive function to traverse the categorical data and store the subcategories of each category as its attributes.

④ Return the processed classification data to the front-end display page.

In the process of realizing infinite classification, we need to use recursive functions, because there is a parent-child relationship between categories, each category may have sub-categories, and each sub-category can have its own sub-category. The recursive function can iterate through all categories and store the subcategories of each category as its attributes, allowing for unlimited categories.

6. Summary

Through the introduction of this article, we have learned how to use Nodejs and Express framework to achieve unlimited classification functions. Knowledge points that need to be mastered include Mysql database, Express framework, handwritten SQL statements, API interface design, etc. Additionally, this article explains how to use recursive functions to implement infinite classification logic. I hope this article can help you and make you more proficient in the technology of achieving infinite classification.

The above is the detailed content of Nodejs realizes unlimited classification. For more information, please follow other related articles on the PHP Chinese website!