-- Add password field to customers table for authentication
ALTER TABLE customers ADD COLUMN password_hash VARCHAR(255);

-- Add phone number field if not exists (for registration)
ALTER TABLE customers ADD COLUMN phone_number VARCHAR(20) UNIQUE;

-- Add birth_date field for customer registration
ALTER TABLE customers ADD COLUMN birth_date DATE;

-- Add indexes for better performance
CREATE INDEX idx_customers_phone_number ON customers(phone_number);
CREATE INDEX idx_customers_password_hash ON customers(password_hash) WHERE password_hash IS NOT NULL;

-- Add comments
COMMENT ON COLUMN customers.password_hash IS 'Hashed password for customer authentication';
COMMENT ON COLUMN customers.phone_number IS 'Unique phone number for customer login';
COMMENT ON COLUMN customers.birth_date IS 'Customer birth date for registration';