1.Initialization
const handleDB = require('../handleDB/index')
// Get all navigation
exports.allNav =async (req, res) => {
}
//Update or add navigation
exports.upNav =async (req, res) => {
}
//Delete based on id
exports.delNav = async(req, res) => {
}
2. Database design
aynsc turns the function into an asynchronous function and uses it with await, using the form of arrow function
Simplify(async funtion(){})
How to write an exception:
try {
} catch (error) {
console.error('Error in upNav:', error);
res.send({ code: 500, message: 'Internal server error' });
}
3. Get all front-end navigation categories
// Get all navigation categories
exports.allNav = async (req, res) => {
let result = await handleDB(res, 'book_nav', "find", "Error querying database", { where: `status=0` })
if (result. length == 0) {
res.send({ code: 0, message: "Navigation list is empty" })
}
const total = result.length;
res.send({ code: 200, message: 'Get navigation list successfully', total: total, data: result })
}
4. Update or add navigation
//Update or add navigation
exports.upNav = async (req, res) => {
try {
// Deconstruct the request body
const { navId, ...data } = req.body;
// Check if navId exists
if (navId) {
// If navId exists, update navigation information
const result = await handleDB(res, 'book_nav', 'update', 'Update failed', `navId=${navId}`, data);
// Check if the update is successful
if (result.affectedRows !== 1) {
return res.send({ code: 0, message: 'Failed to update navigation category data!' });
}
res.send({ code: 200, message: 'Updating navigation classification data successfully' });
} else {
// If navId does not exist, add navigation information
// 3. Query the database to see if this user name exists
let result1 = await handleDB(res, "book_nav", "find", "Database query error", { where: `navName="${data.navName}"` })
// 4. If it already exists, return the user name has been registered return
if (result1.length > 0) {
res.send({ code: 0, message: "The navigation category name has been registered, please change other navigation category names!" });
return
}
const result = await handleDB(res, 'book_nav', 'insert', 'Add failed', data);
// Check if the insertion is successful
if (result.affectedRows !== 1) {
return res.send({ code: 0, message: 'Failed to add navigation category data!' });
}
res.send({ code: 200, message: 'Add navigation category data successfully' });
}
} catch (error) {
console.error('Error in upNav:', error);
res.send({ code: 500, message: 'Internal server error' });
}
};
5. Delete based on id
//Delete based on id
exports.delNav = async (req, res) => {
// console.log(11);
const navId = req.params.navId;
if (!navId) {
res.send({ code: 0, message: 'The obtained parameter is empty' })
}
// 3 Query the database according to the ID to see if the navigation category exists
let result = await handleDB(res, "book_nav", "find", "book_nav query error", {
where: `navId = ${navId} AND status = 0`
});
// console.log(result);
// 4 Check whether the navigation with the specified id exists
if (result.length !== 1) return res.send({ code: 0, message: 'This category does not exist!' })
let results = await handleDB(res, "book_nav", "update", "Error in querying data!", `navId= ${navId}`, { status: 1 });
// 6 SQL statement is executed successfully, but the number of rows affected is not equal to 1
if (results.affectedRows !== 1) return res.send({ code: 0, message: 'Failed to delete navigation category!' })
res.send({ code: 200, message: 'Delete navigation category successfully', });
}
6. Get different book product lists based on id
// Get different book products based on different IDs
exports.getProduct = async (req, res) => {
const id = req.params.id;
if (!id) {
return res.send({ code: 0, message: 'The obtained parameter is empty' })
}
// 3 Query the database according to the ID to see if the product exists
let result = await handleDB(res, "book_product", "find", "book_product query error", {
where: `product_id = ${id} AND status = 0`
});
// console.log(result);
// 4 Check whether the product with the specified id exists
if (result.length == 0) return res.send({ code: 0, message: 'The product list is empty!' })
const total = result.length
res.send({ code: 200, message: "Getting product list successfully", total: total, data: result })
}
