Fix up null values on latest migration, add notes

db/migrate/20170330021336_add_counter_caches.rb

@@ -1,9 +1,13 @@
 class AddCounterCaches < ActiveRecord::Migration[5.0]
   def change
-    add_column :statuses, :favourites_count, :integer
-    add_column :statuses, :reblogs_count, :integer
-    add_column :accounts, :statuses_count, :integer
-    add_column :accounts, :followers_count, :integer
-    add_column :accounts, :following_count, :integer
+    add_column :statuses, :favourites_count, :integer, null: false, default: 0
+    add_column :statuses, :reblogs_count, :integer, null: false, default: 0
+    add_column :accounts, :statuses_count, :integer, null: false, default: 0
+    add_column :accounts, :followers_count, :integer, null: false, default: 0
+    add_column :accounts, :following_count, :integer, null: false, default: 0
   end
 end
+
+# To make the new fields contain correct data:
+# update statuses set favourites_count = (select count(*) from favourites where favourites.status_id = statuses.id), reblogs_count = (select count(*) from statuses as reblogs where reblogs.reblog_of_id = statuses.id);
+# update accounts set statuses_count = (select count(*) from statuses where account_id = accounts.id), followers_count = (select count(*) from follows where target_account_id = accounts.id), following_count = (select count(*) from follows where account_id = accounts.id);

db/schema.rb

@@ -44,9 +44,9 @@ ActiveRecord::Schema.define(version: 20170330021336) do
     t.boolean  "suspended",               default: false, null: false
     t.boolean  "locked",                  default: false, null: false
     t.string   "header_remote_url",       default: "",    null: false
-    t.integer  "statuses_count"
-    t.integer  "followers_count"
-    t.integer  "following_count"
+    t.integer  "statuses_count",          default: 0,     null: false
+    t.integer  "followers_count",         default: 0,     null: false
+    t.integer  "following_count",         default: 0,     null: false
     t.index "(((setweight(to_tsvector('simple'::regconfig, (display_name)::text), 'A'::\"char\") || setweight(to_tsvector('simple'::regconfig, (username)::text), 'B'::\"char\")) || setweight(to_tsvector('simple'::regconfig, (COALESCE(domain, ''::character varying))::text), 'C'::\"char\")))", name: "search_index", using: :gin
     t.index "lower((username)::text), lower((domain)::text)", name: "index_accounts_on_username_and_domain_lower", using: :btree
     t.index ["username", "domain"], name: "index_accounts_on_username_and_domain", unique: true, using: :btree
@@ -223,8 +223,8 @@ ActiveRecord::Schema.define(version: 20170330021336) do
     t.integer  "application_id"
     t.text     "spoiler_text",           default: "",    null: false
     t.boolean  "reply",                  default: false
-    t.integer  "favourites_count"
-    t.integer  "reblogs_count"
+    t.integer  "favourites_count",       default: 0,     null: false
+    t.integer  "reblogs_count",          default: 0,     null: false
     t.index ["account_id"], name: "index_statuses_on_account_id", using: :btree
     t.index ["in_reply_to_id"], name: "index_statuses_on_in_reply_to_id", using: :btree
     t.index ["reblog_of_id"], name: "index_statuses_on_reblog_of_id", using: :btree