@startuml

skinparam linetype ortho

entity "records" {
	id: primary
	--
	date: varchar(10) [YYYY-MM-DD]
	start: varchar(5) [HH:MM]
	end: varchar(5) [HH:MM]

	created: timestamp
}

entity "records_history" {
	id: primary
	--
	record: records::id

	date: varchar(10)
	start: varchar(5)
	end: varchar(5)

	modified_at: timestamp
}

entity "estimates" {
	id: primary
	--
	year: integer
	month: integer
	estimate: real
	
	created: timestamp
}

entity "estimates_history" {
	id: primary
	--
	estimate: estimates::id

	year: integer
	month: integer
	estimate: real
	
	modified_at: timestamp
}

@enduml