问题描述
rails中的"add_foreign_key" 和"add_reference" 方法有什么区别?
What is the difference between "add_foreign_key" and "add_reference" methods in rails?
据Rails官方指南，我所了解的是，它们都用于在两个表之间创建外键约束.
According to rails official guide all I understand is that they both are used to create foreign key constraint between two tables.
推荐答案
add_foreign_key-添加新的外键. from_table是带有键列的表，to_table包含引用的主键.
add_foreign_key - adds a new foreign key. from_table is the table with the key column, to_table contains the referenced primary key.
add_reference-是同时创建列，索引和外键的快捷方式.
add_reference - is meant as a shortcut for creating a column, index and foreign key at the same time.
什么是foreign key-外键是表中的一个字段或一组字段，可以唯一地标识另一个表中的行.
What is foreign key - a foreign key is a field or group of fields in a table that uniquely identifies a row in another table.
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