PHP and UniApp realize the association between data tables

PHP and UniApp implement the association between data tables

Introduction:
In Web applications, the association between data tables is a very common requirement. For example, in an e-commerce website, there is a relationship between orders and products, and the purchased product information needs to be stored in the order. In this article, we will explore how to implement associations between data tables using PHP and UniApp, and provide code examples.

1. Association in PHP
In PHP, you can use associative array (Associative Array) to realize the association between data tables. An associative array is a data structure that associates keys and values.

The following is an example that demonstrates how to implement an association between two data tables in PHP. Suppose we have two data tables: orders table (orders) and product table (products).

orders table structure:

CREATE TABLE orders (
  id INT PRIMARY KEY AUTO_INCREMENT,
  product_id INT,
  quantity INT
);

products table structure:

CREATE TABLE products (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(100),
  price DECIMAL(10, 2)
);

Now, we want to store product-related information in the orders table, so we need an associative array to store it Product id, name and price.

// 通过查询商品表获取商品信息
$product_id = 1;
$query = "SELECT * FROM products WHERE id = $product_id";
$result = mysqli_query($con, $query);
$product = mysqli_fetch_assoc($result);

// 将商品信息存储到订单表
$order = array(
  'product_id' => $product['id'],
  'product_name' => $product['name'],
  'product_price' => $product['price'],
  'quantity' => 2
);

// 将关联数组插入到订单表
$query = "INSERT INTO orders (product_id, quantity) VALUES ('".$order['product_id']."', '".$order['quantity']."')";
mysqli_query($con, $query);

In the above code example, we first obtain product information by querying the product table and store it in the associative array $product. Then, we insert the relevant information in the $product array into the orders table.

2. Associations in UniApp
UniApp is a cross-platform development framework that can use HTML, CSS and JavaScript to write mobile applications. UniApp uses Vue.js as the underlying framework to realize the association between data tables.

The following is an example that demonstrates how to implement the association between two data tables in UniApp. Suppose we have two data tables: orders table (orders) and product table (products).

orders table structure:

CREATE TABLE orders (
  id INT PRIMARY KEY AUTO_INCREMENT,
  product_id INT,
  quantity INT
);

products table structure:

CREATE TABLE products (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(100),
  price DECIMAL(10, 2)
);

Now, we want to store product-related information in the orders table, so we need an associated object to store it. Product id, name and price.

<template>
  <div>
    <button @click="addOrder">添加订单</button>
  </div>
</template>

<script>
export default {
  methods: {
    addOrder() {
      // 通过查询商品表获取商品信息
      let productId = 1;
      uni.request({
        url: '/api/products/' + productId,
        method: 'GET',
        success: (res) => {
          let product = res.data;

          // 将商品信息存储到订单表
          let order = {
            productId: product.id,
            productName: product.name,
            productPrice: product.price,
            quantity: 2
          };

          // 将关联对象插入到订单表
          uni.request({
            url: '/api/orders',
            method: 'POST',
            data: order,
            success: (res) => {
              console.log('添加订单成功');
            }
          });
        }
      });
    }
  }
}
</script>

In the above code example, when the user clicks the "Add Order" button, we first obtain the product information by querying the product table and store it in the associated object product. Then, we insert the relevant information in the product object into the order table.

Conclusion:
Through PHP and UniApp, we can easily realize the association between data tables. In PHP, an associative array is used to store association information; in UniApp, an association object is used to store association information. Whether on the server side or on the mobile side, linked data can be used to meet the needs of your application.

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