How do I get around this relational database design smell?

Question

I have a really simple mediaTypes table which contains the following columns:

id string
name string

Each mediaType record can have many \"place

Answer 1

maybe this is a subjective solution. If the Placements table have no much columns, ej: (detail_col_1, detail_col_2, detail_col_3.. detail_col_6) the table design is not that bad, I mean, it doesn`t depend of how many null columns you got, maybe it looks ugly but it should work. Now, if you want a complex method I'd suggest some of these:

1. Simple Placements table with json in it:

MediaTypes
+ id
+ name

Placements
+ id
+ mediaTypeId
+ name
+ detail

In detail I can define my attributes as json, and set the correct values for each type:

row 1: {'attr1': valx, 'attr2': valy} row 2: {'attr4': valz, 'attr1': valw}

Now, the problem here is the query filter (you cannot). This should work if you want to save extra info.

2. An elegant way:

MediaTypes
+ id
+ name

Placements
+ id
+ mediaTypeId
+ name

DetailAttributes //table of attributes for any type 
+ id
+ name
+ mediaTypeId

PlacementDetailAttributes //many to many rel between DetailAttributes&Placements
+ placementId
+ detailAttributeId
+ value

With this approach you can add many attributes as you want. Query filter by attributes should work too!!