Active Record will automatically record creation and/or update timestamps of database objects if fields named created_at/created_on or updated_at/updated_on are present.
From the timestamp.rb file:
created_on: date onlycreated_at: date and time- same for @updatedat@/
updated_onfields_
leeo: While this is a commonly held convention, I don’t see it referenced in the Rails source anywhere. More importantly, at/on doesn’t actually affect the value or type of data being stored. Rails simply throws a Time in there, which gets cast into a Date if so required by the schema.
Notes
Note: timestamp fields are not supported by default. Use a datetime field instead.
Note: Use :timestamp as the column type when defining your migrations. ActiveRecord will automatically convert it to the correct column type for whatever database you run it against.
Note: MUST create these fields Nullable with no default on your database. The value-injector code within timestamp.rb (below) depends upon the initial values of these fields to be NIL and the field to be Nullable.
PostgreSQL note: You need to use timestamp for the created_at et al fields
Questions
Q: is this referring to the SQL timestamp data type, or to the MySQL timestamp “feature”?
A: This feature is not dependant on DB-specific automatic timestamping fields/behaviours, it is handled by ActiveRecord.
Q: What is the difference between created_on and created_at if they both have to be datetime fields?
A: There is no difference. The two are treated the same. (They ARE different for Oracle)
(Doesn’t the one save a Time, and the other one a Date object? When you access the created_at or created_on after saving, doesn’t the one give you a Time object, the other a Date object?
—Scott Taylor
)
Q: What if I don’t want _updated_at_ to be automatically handled? I want to update _updated_at_ only in a particular situation…
A: The documentation explains how to disable automatic timestamping.
Q: Why aren’t these fields populated when loading fixtures?
Q: I am struggling with the same question. I loaded a YAML fixture to test and the created_at and updated_at fields won’t take on the values in my YAML file. I even tried it manually in the migration code and it would not work.
category: MagicFieldNames
Q: Why aren’t there answers to these last two?
Active Record will automatically record creation and/or update timestamps of database objects if fields named created_at/created_on or updated_at/updated_on are present.
From the timestamp.rb file:
created_on: date onlycreated_at: date and time- same for @updatedat@/
updated_onfields_
leeo: While this is a commonly held convention, I don’t see it referenced in the Rails source anywhere. More importantly, at/on doesn’t actually affect the value or type of data being stored. Rails simply throws a Time in there, which gets cast into a Date if so required by the schema.
Notes
Note: timestamp fields are not supported by default. Use a datetime field instead.
Note: Use :timestamp as the column type when defining your migrations. ActiveRecord will automatically convert it to the correct column type for whatever database you run it against.
Note: MUST create these fields Nullable with no default on your database. The value-injector code within timestamp.rb (below) depends upon the initial values of these fields to be NIL and the field to be Nullable.
PostgreSQL note: You need to use timestamp for the created_at et al fields
Questions
Q: is this referring to the SQL timestamp data type, or to the MySQL timestamp “feature”?
A: This feature is not dependant on DB-specific automatic timestamping fields/behaviours, it is handled by ActiveRecord.
Q: What is the difference between created_on and created_at if they both have to be datetime fields?
A: There is no difference. The two are treated the same. (They ARE different for Oracle)
(Doesn’t the one save a Time, and the other one a Date object? When you access the created_at or created_on after saving, doesn’t the one give you a Time object, the other a Date object?
—Scott Taylor
)
Q: What if I don’t want _updated_at_ to be automatically handled? I want to update _updated_at_ only in a particular situation…
A: The documentation explains how to disable automatic timestamping.
Q: Why aren’t these fields populated when loading fixtures?
Q: I am struggling with the same question. I loaded a YAML fixture to test and the created_at and updated_at fields won’t take on the values in my YAML file. I even tried it manually in the migration code and it would not work.
category: MagicFieldNames
Q: Why aren’t there answers to these last two?