code: private void validateRelationship(String baseTableName,
  			String relatedTableName, String relationName) {
  
  		// Verify the base and related tables exist
  		if (!geoPackage.isTable(baseTableName)) {
  			throw new GeoPackageException(
  					"Base Relationship table does not exist: " + baseTableName
  							+ ", Relation: " + relationName);
  		}
  		if (!geoPackage.isTable(relatedTableName)) {
  			throw new GeoPackageException(
  					"Related Relationship table does not exist: "
  							+ relatedTableName + ", Relation: " + relationName);
  		}
  
  		// Verify spec defined relation types
  		RelationType relationType = RelationType.fromName(relationName);
  		if (relationType != null) {
  			validateRelationship(baseTableName, relatedTableName, relationType);
  		}
  
  	}
docs: Validate that the relation name is valid between the base and related
  table
  
  @param baseTableName
  base table name
  @param relatedTableName
  related table name
  @param relationName
  relation name