Rails SQL Query

Question

In the following block of code, on what line is the SQL actually executed on the database?

first_name, last_name = @name.split(", ")
people = Person.where(first_name: first_name)
people = people.limit(5)
people.each do |person|
  puts person
end

Thanks

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Marek Lipka
– Marek Lipka

2016-02-05 09:56:38 +00:00
Commented Feb 5, 2016 at 9:56 — Marek Lipka
– Marek Lipka, Commented Feb 5, 2016 at 9:56

Marek Lipka · Accepted Answer · 2016-02-05 10:58:56Z

4

SQL query is executed in people.each do |person| line because only then Rails need the result of this query. Rails execute SQL only when it's literally needed, not when you build your scope. It's called lazy loading.

edited Feb 5, 2016 at 10:58

answered Feb 5, 2016 at 9:02

Marek Lipka

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2 Comments

Chimed Palden Over a year ago

But should it be in line 2 and line 3. Can you explain your answer pls.

Marek Lipka Over a year ago

I edited my answer. No, it should not be in line 2 and line 3 because rails don't need the result of this query in these lines.

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