Temporary Tables, Big Responsibilities: Maintaining Data Consistency during Operations

Here's the problem: if you add new customers or modify existing ones after creating the backup, the temporary table won't reflect these changes. This inconsistency can lead to issues if you need to restore from the backup.

-- Create the original table
CREATE TABLE Customers (
  CustomerID INT PRIMARY KEY,
  Name VARCHAR(50),
  Address VARCHAR(100)
);

-- Insert some initial data
INSERT INTO Customers (CustomerID, Name, Address)
VALUES (1, 'foo', '123 Main St'),
       (2, 'Jane Smith', '456 Elm St');

-- Create a temporary backup table
CREATE TABLE TempCustomers (
  CustomerID INT PRIMARY KEY,
  Name VARCHAR(50),
  Address VARCHAR(100)
);

-- Insert data from original table into backup
INSERT INTO TempCustomers SELECT * FROM Customers;

-- Add a new customer to the original table (not reflected in backup)
INSERT INTO Customers (CustomerID, Name, Address)
VALUES (3, 'foo Jones', '789 Oak Ave');

-- Now, the two tables are inconsistent!

Related Issues:

• Data loss: If you need to restore from the backup, you'll lose any changes made to the original table after the backup was created.
• Incorrect data: If you use outdated information from the backup, it can lead to errors and inconsistencies in your application logic.

• Triggers: You can create triggers on the original table that automatically insert or update the corresponding rows in the temporary backup table whenever the original table is modified. This approach requires careful planning and can become complex for intricate table structures.
• Periodic updates: You can periodically refresh the temporary backup table by copying the latest data from the original table. This is simpler but might introduce a slight delay and requires scheduling the updates.
• Combined approach: Combine triggers for critical updates and periodic refreshes for less frequent changes. This balances complexity with accuracy.