Three Ways to Make Database Queries in Rails

In Rails, querying the record(s) from database can be done through the following methods:

1. find(*arguments)
   • Find records by their IDs
   • Raises exception (ActiveRecord::RecordNotFound) if no record is found
2. find_by(argument, *arguments)
   • Finds the first record matching the specified conditions
   • Returns nil if no record is found
   • find_by!(argument, *arguments) raises ActiveRecord::RecordNotFound like find() if no record is found
3. where(options = :chain, *rest)
   • Refer to How to Use The Rails Where Method (with Examples), starting from “Basic Where Conditions”, for examples and their use cases

Refs

• How to Use The Rails Where Method (with Examples)
• ActiveRecord::FinderMethods
• ActiveRecord::QueryMethods