Default value of column should have additional information to identify if default value is auto-generated

[pavish]

Description

When the default value is auto-generated, the returned value is a string representing the procedure call.

Eg., for all PKs for the default id column, the value for default is "nextval('\"public\".data_types_id_seq'::regclass)".

We need additional information to help the client differentiate this from a normal string value.

Expected behavior

It would be better if default returned an object, something similar to:

default: {
   type: 'constant' // auto-generated or constant
   value: 'some default value'
}

For auto-generated values, we could send additional information based on how we intend to support formulas, procedures and functions in the future. For now, we can just send the same value and on the frontend the input can be disabled.

[pavish]

@kgodey Marking this issue as draft inorder to decide on the format for the default value returned in the columns endpoint.

[mathemancer]

@pavish I have a quick implementation that uses:

...
"default": {
    "default_value": <some_val>
    "is_dynamic": <true|false>  // This is read-only
}
...

Does that work?

[mathemancer]

As for the cruddy-looking output for dynamic defaults, I'm thinking we just use that for now so the user can at least see what's happening if they know how it works. We'll need to do other things when we have the ability to work with dynamic defaults better.

[pavish]

@mathemancer I think this format works. We could always extend this object when we need to provide additional information.