DB: How to set up a many to many table(s) to handle multiple selectable conditions - sql

Question

I am working on a search filter for a website that will help users find a venue(for get-togethers and ceremonies) that meets their needs. Filters would include such things as: style, amenities, event type, etc. Multiple options in a category can apply to a venue, so a user can select multiple options from style, amenities and event type categories when searching.
My issue is in how I should approach the table design in the database. Currently I have a Venue table with a unique id and basic information, and a number of tables representing each category (style, amenities, etc) where they contain an id and name field.
I know that I need an intermediary table to hold foreign keys, so each option applicable to a category is associated to the venue.
Option 1: Create for each category table a many to many intermediary table with foreign keys to that category and the venue.
Option 2: Create one large intermediary table with foreign keys for every category, as well as the Venue
i.e.
fk_venue
fk_style
fk_amenities
...
I am trying to decide what is more efficient and less of a problem in coding for. Option 1 would require a query to each table which may become complicated to work with, where as option 2 seems easier to query but might have a much larger number of records to handle a venue with many amenities AND event types for example.
This doesn't seem like a new problem but I have had trouble finding resources that detail how best to approach this. We are currently using MSSQL for the DB and are building the site using .net core.

Answer 1

Go with option one. Create a join table to record the many-to-many relationships of each available feature of a venue. Option 2 is very wasteful in terms of storage. Consider a case where you have a venue with only one amenity, when 50 amenities types are available. Also, as I understand what you are suggesting for option 2, you would have to update your database design each time you add an amenity, event_type, or style. That would be a very difficult thing support wise.
In the case of Option 1, some of the tables would be:
Table Name: venue_amenities
Columns: venue_id, amenity_id
Table Name: venue_event_types
Columns: venue_id, event_type_id
Table Name: venue_styles
Columns: venue_id, style_id
When you query everything with a filter, you could query it like:
select distinct
v.venue_id
from venues v
inner join venue_amenities va on v.venue_id = va.venue_id
inner join venue_event_types vet on v.venue_id = vet.venue_id
inner join venue_styles vs on v.venue_id = vs.venue_id
where va.amenity_id in ([selected amenities])
and vet.event_type_id in ([selected event types])
and vs.venue_style in ([selected styles])

Answer 2

Option 3: You could start out with a meta data design. This would allow you to have multiple records per item or entity.
Often these things evolve with the development of tasks, or the evolution of the process and learning the data or the customer understanding some of the finer details that are drawn out as time goes on.
I've seen similar things where people design for hashtags or white lists, searching for that might get you closer to what you are looking for. Here is a working example to get you started.
declare #venue as table(
VenueID int identity(1,1) not null primary key clustered
, Name_ nvarchar(255) not null
, Address_ nvarchar(255) null
);
declare #venueType as table (
VenueTypeID int identity(1,1) not null primary key clustered
, VenueType nvarchar(255) not null
);
declare #venueStuff as table (
VenueStuffID int identity(1,1) not null primary key clustered
, VenueID int not null -- constraint back to venueid
, VenueTypeID int not null -- constraint to dim or lookup table for ... attribute types
, AttributeValue nvarchar(255) not null
);
insert into #venue (Name_)
select 'Bob''s Funhouse'
insert into #venueStuff (VenueID, VenueTypeID, AttributeValue)
select 1, 1, 'Scarrrrry' union all
select 1, 2, 'Food Avaliable' union all
select 1, 3, 'Game tables provided' union all
select 1, 4, 'Creepy';
insert into #venueType (VenueType)
select 'Haunted House Theme' union all
select 'Gaming' union all
select 'Concessions' union all
select 'post apocalyptic';
select a.Name_
, b.AttributeValue
, c.VenueType
from #venue a
join #venueStuff b
on a.VenueID = b.VenueID
join #venueType c
on c.VenueTypeID = b.VenueTypeID