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One Rails project I had got sidelined for a good 6 hours because ActiveRecord requires IDs on everything. The documentation says that you can skip IDs, but when

by trebor 15y ago

One Rails project I had got sidelined for a good 6 hours because ActiveRecord requires IDs on everything. The documentation says that you can skip IDs, but when you try to save it crashes every time. Go figure whose fault that one is.

rahoulb 15y ago
I'm interested - where did you learn that ActiveRecord does not require IDs? The only case where I can think of where it doesn't require IDs is when building a join table (for a many-to-many relationship). In every other case, you need to specify a primary key field (although it does not need to be an auto-incrementing integer called "id") and I'm sure it says as much in the docs. EDIT: You can do a select and omit the ID field in the resultset, but you cannot save the results back again - simply because it does not know where to write it back. Again, I'm pretty sure I remember reading that in the docs, but I may have imagined it.
- trebor 15y ago
  http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-create_table http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAd... create_table(:categories_suppliers, :id => false) do |t| t.column :category_id, :integer t.column :supplier_id, :integer end I did this and indexed the table by date, and it works for everything except saving a record. Like I said, an ID/primary key is required though that section of the documentation implies that an ID is optional.
  - rahoulb 15y ago
    Hmm - yeah the docs are sort of unclear, if you're not familiar with the convention. :categories_suppliers implies that the table is a join table (a many-to-many join between categories and suppliers) - which is why it has no ID and why it only has the two foreign key fields with no other data.
    - trebor 15y ago
      Yet the assumption that all models require an ID is a fallacy. I was generating reports unique to the day, therefore a simple Date field was adequate as an index/ID. I don't know about other ORMs but when working directly with the SQL it'd be no issue. I hold out that it's a problem in the design of ActiveRecord to assume that there will always be a primary key. That said, if I can just tell the model "identify yourself by this key" WITHOUT setting it as the primary key I would be happy.
sleepyhead 15y ago
http://api.rubyonrails.org/classes/ActiveRecord/AttributeMethods/PrimaryKey/ClassMethods.html#method-i-set_primary_key http://api.rubyonrails.org/classes/ActiveRecord/AttributeMet... http://guides.rubyonrails.org/migrations.html#writing-a-migration http://guides.rubyonrails.org/migrations.html#writing-a-migr...
- trebor 15y ago
  Are you saying that because I didn't set the date field as my primary key, it crashed?

by trebor 15y ago

rahoulb 15y ago

I'm interested - where did you learn that ActiveRecord does not require IDs? The only case where I can think of where it doesn't require IDs is when building a join table (for a many-to-many relationship). In every other case, you need to specify a primary key field (although it does not need to be an auto-incrementing integer called "id") and I'm sure it says as much in the docs. EDIT: You can do a select and omit the ID field in the resultset, but you cannot save the results back again - simply because it does not know where to write it back. Again, I'm pretty sure I remember reading that in the docs, but I may have imagined it.

trebor 15y ago
http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html#method-i-create_table http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAd... create_table(:categories_suppliers, :id => false) do |t| t.column :category_id, :integer t.column :supplier_id, :integer end I did this and indexed the table by date, and it works for everything except saving a record. Like I said, an ID/primary key is required though that section of the documentation implies that an ID is optional.
- rahoulb 15y ago
  Hmm - yeah the docs are sort of unclear, if you're not familiar with the convention. :categories_suppliers implies that the table is a join table (a many-to-many join between categories and suppliers) - which is why it has no ID and why it only has the two foreign key fields with no other data.
  - trebor 15y ago
    Yet the assumption that all models require an ID is a fallacy. I was generating reports unique to the day, therefore a simple Date field was adequate as an index/ID. I don't know about other ORMs but when working directly with the SQL it'd be no issue. I hold out that it's a problem in the design of ActiveRecord to assume that there will always be a primary key. That said, if I can just tell the model "identify yourself by this key" WITHOUT setting it as the primary key I would be happy.

sleepyhead 15y ago

http://api.rubyonrails.org/classes/ActiveRecord/AttributeMethods/PrimaryKey/ClassMethods.html#method-i-set_primary_key http://api.rubyonrails.org/classes/ActiveRecord/AttributeMet... http://guides.rubyonrails.org/migrations.html#writing-a-migration http://guides.rubyonrails.org/migrations.html#writing-a-migr...

trebor 15y ago
Are you saying that because I didn't set the date field as my primary key, it crashed?