Add Update Column Versus Update Attribute as a rails til

rails/update-column-versus-update-attribute.md

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+# Update Column Versus Update Attribute
+
+Rails offers a whole variety of methods for making updates to the ActiveRecord
+objects in your app. Two unique, infrequently-used ones are
+[`#update_column`](https://devdocs.io/rails~5.2/activerecord/persistence#method-i-update_column)
+and
+[`#update_attribute`](https://devdocs.io/rails~5.2/activerecord/persistence#method-i-update_attribute).
+What is unique about them is that they are both ways of updating a record while
+skipping the validations defined on the model.
+
+So, how do they differ?
+
+A call to `#update_attribute` is still going to trigger any callbacks defined
+on the model and it will touch the `update_at` column. On the other hand,
+`#update_column` can be thought of as a way of directly interacting with the
+database -- callbacks are skipped and you are truly only touching the specified
+column, `updated_at` is left as is.
+
+The docs have this recommendation for `#update_attribute`:
+
+> This is especially useful for boolean flags on existing records.
+
+And for `#update_column`, they say this:
+
+> This is the fastest way to update attributes because it goes straight to the
+> database, but take into account that in consequence the regular update
+> procedures are totally bypassed.
+
+These are both useful in specific situations, but be sure to know their
+differences and to use them with caution.