DatatypeInsideOntop

Datatype handling inside Ontop

Note that this page is only intended for ontop developers

Note that the behavior has changed as described in OntopDatatypes

Datatypes inside ontop:

• SQL data type (DB and mappings) x #DBs,

• java.sql.jdbc.Types

• XSD data types (for Datalog) ans1(xsd:int(x))

• XML Schema

• COL_TYPE (used for the signature of the Predicate)

• CODE (for SQL generation)

• OWL Datatype (for OWLAPI)

• Sesame Datatype (for SESAME API)

• SQL CAST (for SQL Generation, in particular for aggregations)

Datatype conversions:

• OWL datatype -> COL_TYPE

OWLAPI3Translator
		private static Predicate.COL_TYPE getColumnType(OWLDatatype datatype) throws TranslationException 

• Sesame Datatype (XSD type) -> COL_TYPE

SesameRDFIterator
		private Predicate.COL_TYPE getColumnType(URI datatype) 

• COL_TYPE -> Sesame Datatype

SesameBindingSet
      private Binding createBinding(String bindingName) 

• XSD type -> CODE

	SQLGenerator
	private String getTypeColumnForSELECT(Term ht, List<String> signature, int hpos) 

• XSD type -> jdbc Type

	SQLGenerator
	private int getVariableDataType (Term term, QueryAliasIndex idx) 

• CODE -> COL_TYPE

QuestResultset
	private COL_TYPE getQuestType(int sqltype) 

• jdbc Type -> XSD type

TypeMapper
        private static TypeMapper typeMapper;

NOTE: we return the most general XSD datatype from the correspondent database SQL type.

• jdbc Type -> XSD type (use TypeMapper)

MappingDatatypeRepair 
     private Predicate getDataTypeFunctor(Map<String, List<Object[]>> termOccurenceIndex, Variable variable) throws OBDAException 

• jdbc Type -> DB specific type

SQLDialectAdapters
      public String sqlCast(String value, int type)  
      private static Map<Integer, String> SqlDatatypes

• XSD type -> COL_TYPE

SparqlAlgebraToDatalogTranslator
private COL_TYPE getDataType(LiteralImpl node) 

• COL_TYPE -> XSD type

SparqlAlgebraToDatalogTranslator
private Predicate getDataTypePredicate(COL_TYPE dataType) throws RuntimeException 

• XML Schema -> COL_TYPE

SparqlAlgebraToDatalogTranslator
private Function getConstantFunctionTerm(org.openrdf.query.algebra.ValueConstant expr) 

• COL_TYPE -> XSD type

ExpressionEvaluator
private Predicate getDatatypePredicate(Term term) 

##Using Datatypes

• COL_TYPE -> string

JDBCUtil 
        public String getSQLLexicalForm(ValueConstant constant)

• jdbc Type -> boolean true/false

SQLGenerator
	private boolean isStringColType