Update a message

Following the previous examples to create your controller, we will focus on Model operations from now on.

Update a record

To update the record, we need to know the primary key of it. So the id in the route could help us to identify.

Update

GoFrame has a strict rule to use Update() function to update a record, you have to add a where condition in the method chain, otherwise the operation would not be executed.

id := g.RequestFromCtx(ctx).GetRouter("id").Int()
dao.Messages.Ctx(ctx).Where(g.Map{
	dao.Messages.Columns().Id: id,
}).Data(req).Update()

id := g.RequestFromCtx(ctx).GetRouter("id").Int()
g.DB().Model("messages").Where(g.Map{
	dao.Messages.Columns().Id: id,
}).Data(req).Update()

Save

Save() is another convenient function to update a record, we have used it in the message creation part. To update a record with it, your data should contain the primary key.

id := g.RequestFromCtx(ctx).GetRouter("id").Int()
dao.Messages.Ctx(ctx).Data(g.Map{
	dao.Messages.Columns().Id: id,
	dao.Messages.Columns().UserUid: req.UserUid,
	dao.Messages.Columns().Content: req.Content,
}).Save()

id := g.RequestFromCtx(ctx).GetRouter("id").Int()
g.DB().Model("messages").Data(g.Map{
	dao.Messages.Columns().Id: id,
	dao.Messages.Columns().UserUid: req.UserUid,
	dao.Messages.Columns().Content: req.Content,
}).Save()

Database transaction

You may need to use database transaction to ensure the data consistency, since sometimes you may not want to update records if some operations failed. Here is an example:

// ctx is the context in your controller or other functions.
g.DB().Transaction(ctx, func(ctx context.Context, tx gdb.TX) error {
	// Insert a message
	result, err := tx.Ctx(ctx).Insert("messages", g.Map{
		"user_uid": "0000000000",
		"content": "This is a test message.",
	})
	if err != nil {
		return err
	}
	// Get insert message id
	id, err := result.LastInsertId()
	if err != nil {
		return err
	}
    if id < 10 {
        return gerror.New("New message id must be greater than 10")
    }
	return nil
})

In this transaction, first we insert a message in the messages table, and then we get the insert id of the message. Finally we check if the id is greater than 10, if not, we return an error.

In the previous three step, every err thrown would cause the transaction to rollback. The insert operation in this transaction could only be commit if all the condition is met and not error happened.