1 つのアプリケーションでの複数の接続

// Load environment variablesrequire('dotenv').config();
// Establish the secondary MongoDB connectionconst db = require("./db.secondary.js")(process.env.SECONDARY_CONN_STR, {    // (optional) connection options});
// Import Product Schemaconst secondaryProductSchema = require("./product.schema.js")({    collection: "products",    // strict: false // that doesn't adhere strictly to the schema!    // Pass configuration options if needed});
// Base sample products dataconst sampleProducts = [    {        name: "Laptop Pro",        price: 1299.99,        category: "Electronics",        description: "High-performance laptop for professionals"    },    {        name: "Wireless Headphones",        price: 199.99,        category: "Electronics",        description: "Premium noise-cancelling headphones"    },    {        name: "Coffee Maker",        price: 89.99,        category: "Kitchen",        description: "Automatic drip coffee maker"    }];
// Sample store-specific productsconst storeAProducts = sampleProducts.map(product => ({    ...product,    store: { name: "Store A" },    storeId: "A"}));
const storeBProducts = [    {        name: "Gaming Chair",        price: 299.99,        category: "Furniture",        description: "Ergonomic gaming chair with RGB lighting",        store: { name: "Store B" },        storeId: "B"    },    {        name: "Mechanical Keyboard",        price: 149.99,        category: "Electronics",        description: "RGB mechanical gaming keyboard",        store: { name: "Store B" },        storeId: "B"    }];
// Create a connection for 'Store A'const storeA = db.useDb('StoreA');
// Create Modelconst SecondaryStoreAProductModel = storeA.model("Product", secondaryProductSchema);
// Wait for Store A connection to be readystoreA.once('open', async () => {    console.log('Store A database connected, executing operations...');        try {        // Check if products already exist in Store A        const existingCount = await SecondaryStoreAProductModel.countDocuments();        console.log(`Existing products in Store A: ${existingCount}`);                if (existingCount === 0) {            console.log('Inserting sample products into Store A database...');            await SecondaryStoreAProductModel.insertMany(storeAProducts);            console.log('Sample products inserted into Store A database!');        }
        // Find and display a product        let product = await SecondaryStoreAProductModel.findOne();        console.log('Product found in Store A:', product);                // Display all products        const allProducts = await SecondaryStoreAProductModel.find();        console.log(`Total products in Store A: ${allProducts.length}`);    } catch (error) {        console.error('Error with Store A operations:', error);    }});
// Create a connection for 'Store B'const storeB = db.useDb('StoreB');
// Create Modelconst SecondaryStoreBProductModel = storeB.model("Product", secondaryProductSchema);
// Wait for Store B connection to be readystoreB.once('open', async () => {    console.log('Store B database connected, executing operations...');        try {        // Check if products already exist in Store B        const existingCount = await SecondaryStoreBProductModel.countDocuments();        console.log(`Existing products in Store B: ${existingCount}`);                if (existingCount === 0) {            console.log('Inserting sample products into Store B database...');            await SecondaryStoreBProductModel.insertMany(storeBProducts);            console.log('Sample products inserted into Store B database!');        }
        // Find and display a product        let product = await SecondaryStoreBProductModel.findOne();        console.log('Product found in Store B:', product);                // Display all products        const allProducts = await SecondaryStoreBProductModel.find();        console.log(`Total products in Store B: ${allProducts.length}`);    } catch (error) {        console.error('Error with Store B operations:', error);    }});

// Function to get connection object for particular store's databasefunction getStoreConnection(storeId) {    return db.useDb("Store"+storeId, { useCache: true });}
// Create a connection for 'Store A'const store = getStoreConnection("A");
// Create Modelconst SecondaryStoreProductModel = store.model("Product", secondaryProductSchema);
// Wait for store connection to be readystore.once('open', async () => {    console.log('Store A (dynamic) database connected, executing operations...');        try {        // Check if products already exist in the store        const existingCount = await SecondaryStoreProductModel.countDocuments();        console.log(`Existing products in Store A (dynamic): ${existingCount}`);                if (existingCount === 0) {            // Use the same store A products from the previous example            console.log('Inserting sample products into Store A (dynamic) database...');            await SecondaryStoreProductModel.insertMany(storeAProducts);            console.log('Sample products inserted into Store A (dynamic) database!');        }
        // Find and display a product        let product = await SecondaryStoreProductModel.findOne();        console.log('Product found in Store A (dynamic):', product);                // Display all products        const allProducts = await SecondaryStoreProductModel.find();        console.log(`Total products in Store A (dynamic): ${allProducts.length}`);    } catch (error) {        console.error('Error with Store A (dynamic) operations:', error);    }});