# Deep v. Shallow Copies **URL:** \ **Category:** Database\ **Created:** [November 9, 2020, 6:03pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234 "2020-11-09T18:03:04Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![jkesselman2019](https://avatars.discourse-cdn.com/v4/letter/j/db5fbb/32.png) [@jkesselman2019](https://forum.bubble.io/u/jkesselman2019)\ **Post date:** [November 9, 2020, 6:03pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/1 "2020-11-09T18:03:04Z")
When you copy a thing, are references in that thing to other things copied as references or are copies made of the things referenced? When copying a list of things, are just the references in the list copied, or do you get back a list of new things copied from the thinsg in the original list? Thanks ---
**Author:** ![jkesselman2019](https://avatars.discourse-cdn.com/v4/letter/j/db5fbb/32.png) [@jkesselman2019](https://forum.bubble.io/u/jkesselman2019)\ **Post date:** [November 9, 2020, 6:59pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/2 "2020-11-09T18:59:58Z")
Allright, based on experiments, th answer is both ☹ When you copy a list of objects, the objects in the list get duplicated, but their fields get shallow copied. SO I’m now beating my head against how to deep copy a list of lists… Edit: I could do it with a recursive back-end workflow. I wish there was a simpler way though… ---
**Author:** ![NigelG](https://avatars.discourse-cdn.com/v4/letter/n/ea5d25/32.png) [@NigelG](https://forum.bubble.io/u/NigelG)\ **Post date:** [November 9, 2020, 7:22pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/3 "2020-11-09T19:22:00Z")
I think a bit more explanation on “deep copy” would help as we may well be thinking about different things. ---
**Author:** ![cmarchan](https://sea1.discourse-cdn.com/bubble/user_avatar/forum.bubble.io/cmarchan/32/253062_2.png) [@cmarchan](https://forum.bubble.io/u/cmarchan)\ **Post date:** [November 9, 2020, 9:52pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/4 "2020-11-09T21:52:58Z")
Agree with @NigelG. What is meant by deep copy? ---
**Author:** ![jkesselman2019](https://avatars.discourse-cdn.com/v4/letter/j/db5fbb/32.png) [@jkesselman2019](https://forum.bubble.io/u/jkesselman2019)\ **Post date:** [November 9, 2020, 10:24pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/5 "2020-11-09T22:24:51Z")
Deep and Shallow copy are computer science terms. A deep copy of a variable copes the value of the variable so you have 2 separate variables. A shallow copy just copies a refence to a variable (often, but nto always, a memory address) so you have a single variable referred to in multiple ways. In databases, the idea extends by analogy. A deep copy is a new record. A shallow copy is another field referring to the same primary key. ---
**Author:** ![NigelG](https://avatars.discourse-cdn.com/v4/letter/n/ea5d25/32.png) [@NigelG](https://forum.bubble.io/u/NigelG)\ **Post date:** [November 10, 2020, 2:01pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/6 "2020-11-10T14:01:53Z")
I don’t think Bubble will like it, as there is the potential for it to run forever. You can copy a list of things… > **[Bubble Reference](https://bubble.io/reference#Actions.CopyListOfThings)** > > Full reference for each Bubble element, feature, plugin. Bubble is a visual programing language. Instead of typing code, use a visual editor to build applications. ---
**Author:** ![deadpoetnsp](https://sea1.discourse-cdn.com/bubble/user_avatar/forum.bubble.io/deadpoetnsp/32/64992_2.png) [@deadpoetnsp](https://forum.bubble.io/u/deadpoetnsp)\ **Post date:** [November 10, 2020, 6:29pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/7 "2020-11-10T18:29:36Z")
You can try using backend workflows to recursively _create_ Things and then copy the contents. For example, let’s say a User has a list of Posts. Instead of copying User, create a new User, create a list of new Posts, and copy the contents of the posts. ---
**Author:** ![cmarchan](https://sea1.discourse-cdn.com/bubble/user_avatar/forum.bubble.io/cmarchan/32/253062_2.png) [@cmarchan](https://forum.bubble.io/u/cmarchan)\ **Post date:** [November 10, 2020, 7:13pm UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/8 "2020-11-10T19:13:08Z")
@jkesselman2019 It seems nested recursive backend workflows is the way to go. Custom-built as opposed to any vanilla action specific for this use case. ---
**Author:** ![jkesselman2019](https://avatars.discourse-cdn.com/v4/letter/j/db5fbb/32.png) [@jkesselman2019](https://forum.bubble.io/u/jkesselman2019)\ **Post date:** [November 11, 2020, 2:20am UTC](https://forum.bubble.io/t/deep-v-shallow-copies/120234/9 "2020-11-11T02:20:24Z")
Yeah that seems to be the answer for bubble. Avoiding infinite loops on a directed potentially cyclic graph is a relatively easy computer science problem, btw. You just use a node index for already visited nodes. Basic hashtable works great for this.