You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: customercustomerdemo.xo.go
    path of file: ./repos/xo/_examples/northwind/mysql
    
    the code of the file until where you have to start completion: package mysql

// Code generated by xo. DO NOT EDIT.

import (
	"context"
)

// CustomerCustomerDemo represents a row from 'northwind.customer_customer_demo'.
type CustomerCustomerDemo struct {
	CustomerID     string `json:"customer_id"`      // customer_id
	CustomerTypeID string `json:"customer_type_id"` // customer_type_id
	// xo fields
	_exists, _deleted bool
}

// Exists returns true when the [CustomerCustomerDemo] exists in t
    
func (ccd *CustomerCustomerDemo) Insert(ctx context.Context, db DB) error {
	switch {
	case ccd._exists: // already exists
		return logerror(&ErrInsertFailed{ErrAlreadyExists})
	case ccd._deleted: // deleted
		return logerror(&ErrInsertFailed{ErrMarkedForDeletion})
	}
	// insert (manual)
	const sqlstr = `INSERT INTO northwind.customer_customer_demo (` +
		`customer_id, customer_type_id` +
		`) VALUES (` +
		`?, ?` +
		`)`
	// run
	logf(sqlstr, ccd.CustomerID, ccd.CustomerTypeID)
	if _, err := db.ExecContext(ctx, sqlstr, ccd.CustomerID, ccd.CustomerTypeID); err != nil {
		return logerror(err)
	}
	// set exists
	ccd._exists = true
	return nil
}