define how/if to support conditional schema

[philloooo]

[philloooo]

how should it look like?
user says I have these set of fields for my dataset

datasetA {
required A,
required B,
optional C,
optional D
}

datasetB {
required D,
required E,
optional F
}

when I upload my data, I only want to meet the criteria for my dataset
when I go searching, I want to search across all datasets and filter by fields that are applicable to multiple datasets or just one