fix delete category

backend/controllers/category.js

@@ -7,7 +7,7 @@ exports.getAllCategoriesWithPagination = async (req, res) => {
   try {
     const [data, _] = await db.execute(
       "SELECT * FROM Category C ORDER BY C.CategoryID ASC LIMIT ? OFFSET ?",
-      [limit.toString(), offset.toString()],
+      [limit.toString(), offset.toString()]
     );
 
     const [result] = await db.execute("SELECT COUNT(*) AS count FROM Category");
@@ -24,7 +24,7 @@ exports.addCategory = async (req, res) => {
   try {
     const [result] = await db.execute(
       "INSERT INTO Category (Name) VALUES (?)",
-      [name],
+      [name]
     );
     res.json({ message: "Adding new category successfully!" });
   } catch (error) {
@@ -34,15 +34,23 @@ exports.addCategory = async (req, res) => {
 
 exports.removeCategory = async (req, res) => {
   const { id } = req.params;
-
   try {
+    if (id == "1") throw Error("You're not allowed to delete this category!");
+    const [updateResult] = await db.execute(
+      "UPDATE Product SET CategoryID = 1 WHERE CategoryID = ?",
+      [id]
+    );
+
     const [result] = await db.execute(
       `DELETE FROM Category WHERE CategoryID = ?`,
-      [id],
+      [id]
     );
+
     res.json({ message: "Delete category successfully!" });
   } catch (error) {
-    res.json({ error: "Cannot remove category from database!" });
+    res.json({
+      error: error.message || "Cannot remove category from database!",
+    });
   }
 };
 

mysql-code/Init-Data.sql

@@ -72,6 +72,7 @@ VALUES
 INSERT INTO
     Category (Name)
 VALUES
+	('Other'),
     ('Textbooks'),
     ('Electronics'),
     ('Furniture'),
@@ -100,9 +101,8 @@ VALUES
     ('Winter Clothing'),
     ('Photography Equipment'),
     ('Event Tickets'),
-    ('Software Licenses'),
-    ('Transportation (Car Pool)'),
-    ('Other');
+    ('Software Licenses');
+    
 
 -- Insert Products
 INSERT INTO
@@ -454,4 +454,5 @@ VALUES
         1,
         'This is a great fake product! Totally recommend it.',
         5,
-    );
+        '2024-10-02 16:00:00'
+    )

mysql-code/Schema.sql

@@ -28,19 +28,6 @@ CREATE TABLE Category (
     Name VARCHAR(255) NOT NULL
 );
 
-CREATE TABLE Product (
-    ProductID INT AUTO_INCREMENT PRIMARY KEY,
-    Name VARCHAR(255) NOT NULL,
-    Price DECIMAL(10, 2) NOT NULL,
-    StockQuantity INT,
-    UserID INT,
-    Description TEXT,
-    CategoryID INT NOT NULL,
-    Date DATETIME DEFAULT CURRENT_TIMESTAMP,
-    FOREIGN KEY (UserID) REFERENCES User (UserID),
-    FOREIGN KEY (CategoryID) REFERENCES Category (CategoryID)
-);
-
 -- Product Entity
 CREATE TABLE Product (
     ProductID INT AUTO_INCREMENT PRIMARY KEY,
@@ -51,7 +38,7 @@ CREATE TABLE Product (
     Description TEXT,
     CategoryID INT,
     Date DATETIME DEFAULT CURRENT_TIMESTAMP,
-    FOREIGN KEY (UserID) REFERENCES User (UserID) ON DELETE SET NULL,
+    FOREIGN KEY (UserID) REFERENCES User (UserID) ON DELETE CASCADE,
     FOREIGN KEY (CategoryID) REFERENCES Category (CategoryID)
 );
 
@@ -73,7 +60,7 @@ CREATE TABLE Review (
         AND Rating <= 5
     ),
     Date DATETIME DEFAULT CURRENT_TIMESTAMP,
-    FOREIGN KEY (UserID) REFERENCES User (UserID) ON DELETE SET NULL,
+    FOREIGN KEY (UserID) REFERENCES User (UserID) ON DELETE CASCADE,
     FOREIGN KEY (ProductID) REFERENCES Product (ProductID) ON DELETE CASCADE
 );
 
@@ -85,7 +72,7 @@ CREATE TABLE Transaction (
     Date DATETIME DEFAULT CURRENT_TIMESTAMP,
     PaymentStatus VARCHAR(50),
     FOREIGN KEY (UserID) REFERENCES User (UserID) ON DELETE CASCADE,
-    FOREIGN KEY (ProductID) REFERENCES Product (ProductID) ON DELETE SET NULL
+    FOREIGN KEY (ProductID) REFERENCES Product (ProductID) ON DELETE CASCADE
 );
 
 -- Recommendation Entity (Many-to-One with User, Many-to-One with Product)