如果记录已存在MySQL，则INSERT或UPDATE

I need to write a MySQL query for insert or update some fields. I've seen about the ON DUPLICATE KEY, but my fields are not PRIMARY KEY or UNIQUE, only the combination is unique. Here is the fields list:

ID (PRIMARY KEY AUTOINCREMENT BIGINT), user (BIGINT), creator (BIGINT), type (TINYINT), value (BIGINT), date (INT), readed (TINYINT), erased (TINYINT).

The table name is notifications (if it can be useful). I need to insert a new record or update the existent one if the user, creator, type, values are all the same of the values to insert (so like AND). How I can do that?

You can create a unique index on the variable. I'm not sure which are the variables in question, but here is an example:

create unique index idx_table_user_creator_type on table(user, creator, type)

You can also do this in the create table statement as well, using the syntax for a unique constraint.

You would then use the constraint as:

insert into table(user, creator, type, col1, . . .)
    values(@user, @creator, @type, . . .)
    on duplicate key update col1 = values(col1),
                            col2 = values(col2),
                            . . . ;