replace negative args such as `no-schema` with positive ones

[lichunzhu]

Feature Request

Is your feature request related to a problem? Please describe:

Negative args are very confusing for users to understand especially for the bool variables. Use positive ones will make it clearer.

Describe the feature you'd like:

Replace negative args such as no-schema with positive ones. For example, replace no-schema with exist-schema or something else.

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Optimization:

[kennytm]

The only two negative config currently are no-schema and not-null.