CODEWITHSUNDEEP
databasetagsnormalizationtag-cloud
Artilheiro
Artilheiro

Reputation: 4005

How to model tags in the database?

I have an existing webapp and want to add a tag feature so that users can tag existing objects. The question is should I add a tag column to each object? or should I normalize it and use a tag table where each object will have a collection of tags? I am leaning towards the latter because it feels cleaner, easier to report on and easier to create a tag cloud. But since I know this has been solved 1000 times I wanted to ask and see if I am missing something?

Upvotes: 10

Views: 3289

Answers (3)

OMG Ponies
OMG Ponies

Reputation: 332571

Do you foresee users needing to associate more than one tag with an object?

If not, add the TAG_ID fk to the OBJECT table. Otherwise, you'd need three tables in total to correctly model a many-to-many relationship:

OBJECT

  • OBJECT_ID (pk)

OBJECT_TAG_XREF

  • OBJECT_ID (pk, fk to OBJECT)
  • TAG_ID (pk, fk to TAG)

TAG

  • TAG_ID (pk)

Upvotes: 8

Lucas Oman
Lucas Oman

Reputation: 15872

Definitely normalize. A table for tags, a table for your existing objects, and a table of links between them.

Upvotes: 3

chaos
chaos

Reputation: 124297

Yes, you should normalize it. The 'tag column' is either going to support only one tag per record, or is going to have hideous search performance.

Upvotes: 4

Related Questions