What do the meanings of SELECT, FROM, WHERE, LIMIT, etc. displayed when using rails c?
Since the cause was not understood in the state that DB was not received, I am investigating as follows, but I cannot read it.

2.6.3: 001>Book.all
  Book Load (1.6ms) SELECT "books". * FROM "books"
2.6.3: 001>Book.find (1)
  Book Load (0.1ms) SELECT "books". * FROM "books" WHERE "books". "Id" =? LIMIT? [["Id", 1], ["LIMIT", 1]]
Traceback (most recent call last):
       16: from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport- `load '
       15: from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport- `load_dependency '
       14: from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport- `block in load '
       13: from /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/activesupport-

Because I haven't used rails c almost before, this is a rudimentary question.