Schema
1. Resource hierarchy
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(1.1) Project extends Resource
(1.2) InformationResource extends Resource
It has a parent: Project
(1.2.1) Dataset extends InformationResource
It has children: set of DataTable
(1.2.2) Document extends InformationResource
(1.2.3) CodingSheet extends InformationResource
It has children: set ofCodingRule
(1.2.4) Ontology extends InformationResource
(1.3) DataTable extends Resource
It has a parent: Dataset
It has children: set of DataTableDataTableColumn
(1.4) DataTableColumn extends Resource
It has a parent: DataTable
(1.5) CodingRule is also a resource table, but it does NOT extend Resource because the id sequence is too large.
It has a parent: CodingSheet
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