使用 django 在前端显示来自 sql 数据库的数据

Question

For fetching data from databases, I usually see people create a class in models.py and they migrate it, and then they fetch data from databases and show it on the front-end. my question is, i already have a database which has student_info table and has lots of data. I don't want to define student_info class in models.py and do migration. Instead, since i already have student_info data in sql database . so I want to fetch it directly. can i do so?

one method i know of doing the same, is directly connecting sql server in views.py as;

mydb=mysql.connector.connect(host="localhost",user="root",password="******",database=database_name)

and fetching the data and passing it as variable in index.html . But the problem is, it fetches data only once, and if i refresh the page where local server is running, all the content will disappear, and server will report Broken pipe from ('127.0.0.1', 59579) and to see the data, again i need to restart the sever.

Kindly looking for a better approach to show data on front-end from the existing databases

Answer 1

What you could do is a simple thing for the solution.

Create a StudentData(models.Model) class which will store your data in them as model objects And define all the attributes/ columns in models according to the data and which is in the student_info table.

Write a simple script ( using pymysql ) to retrive all the data from the student_table , store it in text file . ( This part is easy )

take that text file and now in your django project , run a shell command or create a new script to transfer the text_file student data to model objects and save them . Now you have your data .

I think this will work fine . If you also want code . I'll include it.

The code for the solution :

An Update : I have used pymysql for this scripts , i think mysqlconnector will also do the work.

Create a folder inside your project named "Creating Database model" ( you can choose whatever you want but I created the files and all script inside this folder )

first_file : "data retreiving.py"

import pymysql as psql
import os
connection = psql.connect(
    user = "root" , 
    password = os.environ.get("MYSQL_PASSWORD") , 
    database = "college" ,    
)
cursor = connection.cursor()
cursor.execute("select * from student") ;
data_text_file = open("Creating Database model/text_data.txt" , "w")

for row in cursor :
    temp_string = ""
    for data in row :
        temp_string+= "{} ".format(str(data)) 
    data_text_file.write(temp_string+"\n")
data_text_file.close()

Enter your password for connection. Here I am using college database which has student table with some student data . Then I am creating a file text_data.txt which will have the text data of the table . I used string formatting here for convinence and better retrival of data on the other side.

My student table schema has five fields : id , first_name, last_name , age , branch

so my models.py according to this database is here . You create your own according to your requirement.

from django.db import models

class StudentData(models.Model) :
    first_name = models.CharField(max_length = 100 , required = True)
    last_name  = models.CharField(max_length = 100 , required = True)
    age        = models.IntegerField(max_length = 100 , required = True)
    branch     = models.CharField(max_length = 100 , required = True)
    
    def __str__(self) :
        return "{} {}".format(first_name , last_name)  

second file : "data entry in models.py"

This file takes data and then saves it to the model . And you get your database in django .

with open("Creating Database model/text_data.txt") as f :
    data = f.read()
    
new_data_list = []

data = data.split("\n")
new_data_list = []
for i in data :
    temp_list = i.split(" ")[:-1]
    new_data_list.append(temp_list)
data = new_data_list[:-1]

for i in data :
    student_info = StudentModel(
        first_name = i[1] , 
        last_name = i[2] ,
        age = i[3] ,
        branch = i[4] 
    )
    studnet_info.save()

These all are within the "Creating Database model" folder.

This will do all the work you require. Make sure to debug and understand before committing to database.