Most often, additional information (such as materials, countries, currencies, etc.) will not differ within one case.
Therefore, it is reasonable to split the event log into (at least) two tables:
An activity table and a case table.
The activity table usually has the same structure as a minimal event log (potentially including a sorting column).
Also, activity-specific information can be added to the activity table, such as the user which performed an activity in the IT system.
Activity table consisting of minimal event log, sorting and one activity-specific information column.
The case table may contain case-specific information and will be linked to the activity table over a foreign key relation.
The Case ID must be a primary key of the case table (i.e. each Case ID appears only once in the case table). Hence, the information is only stored once per case.
This prevents unnecessary data explosion.
Case table with three case-specific columns.
It can make sense to extend the data model with further metadata on your processes' cases. You can simply add those additional tables and join them to the cases via a foreign key relation.