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## The AdminJS Data model
Before you dive into the details of the flat helpers, let me briefly introduce the way how the
database data is stored in AdminJS.
### The Simple Case
On the backend all the information from DataBase tables/collections goes to {@BaseRecord#params}
object. Usually, it is a `{key: value}` store where `key` is a table name, and value could be
either a string, a number, or an instance of Date() etc.
On the Frontend - these values go to the corresponding {@link RecordJSON.params} property.
This is an example `params` property in the "simple case":
```javascript
params: {
name: 'John',
surname: 'Doe',
age: 28,
}
```
### The Real World Case
In the real world:
* databases have nested JSONB properties or Mixed Schemas
* developers would like to send more complicated data from the Fronted to the backend as arrays.
To achieve that we "flatten" all the data before saving them to `params` property.
So in the real world params could look like:
```javascript
params: {
name: 'John',
surname: 'Doe',
age: 28,
// nested objects
'auth.facebook': 'some login token',
'auth.twitter': 'twitter login token',
// arrays
'interests.0': 'running',
'interests.1': 'jogging',
}
```
and all the data can be even nested on the deeper levels.
### Why we did that?
An alternative solution would be to store an entire raw object and don't care. But there are 2
reasons why we picked this one.
**1. storing selected data in the database**
If you send to the ORM unflatten save request like this:
```javascript
Model.save({{ auth: { facebook: 'newFacebookToken' } }})
```
it will override an entire `auth` property, so from the example above, we will lose `auth.twitter`.
In the second (flatten) case:
```javascript
Model.save({ `auth.facebook`: 'newFacebookToken' }})
```
ORM should keep the value of the `auth.twitter`
> The above is true for Mongoose adapter which is the most advanced regarding handing mixed values
**2. Sending data between the Frontend and the Backend in {@link https://developer.mozilla.org/en-US/docs/Web/API/FormData FormData} format**
AdminJS allows you to upload Files from the Frontend to the Backend. The most optimal way of
doing that is by using {@link https://developer.mozilla.org/en-US/docs/Web/API/FormData FormData}.
But, this requires that values for all the fields are send in `[key: string]: string` form.
And this, as you might guess, fits perfectly to our flatten `params` logic.
### Consequences
Flattening in AdminJS has its consequences everywhere where you use
- {@link BaseRecord} and
- {@link RecordJSON},
because instead of raw object you have it's flatten version.
Also, (as mentioned) the `payload` send to the backed is also flattened.
There you should use helpers gathered in {@link flat} |