Remove Series.schema.

Author: ueshin

databricks/koalas/indexing.py

@@ -392,7 +392,7 @@ def raiseNotImplemented(description):
                 stop = rows_sel.stop
 
                 index_column = self._kdf.index.to_series()
-                index_data_type = index_column.schema[0].dataType
+                index_data_type = index_column.spark_type
                 cond = []
                 if start is not None:
                     cond.append(index_column._scol >= F.lit(start).cast(index_data_type))
@@ -414,7 +414,7 @@ def raiseNotImplemented(description):
                 sdf = sdf.where(F.lit(False))
             elif len(self._kdf._internal.index_columns) == 1:
                 index_column = self._kdf.index.to_series()
-                index_data_type = index_column.schema[0].dataType
+                index_data_type = index_column.spark_type
                 if len(rows_sel) == 1:
                     sdf = sdf.where(
                         index_column._scol == F.lit(rows_sel[0]).cast(index_data_type))

databricks/koalas/internal.py

@@ -536,7 +536,7 @@ def scol_for(self, column_name_or_index: Union[str, Tuple[str, ...]]) -> spark.C
 
     def spark_type_for(self, column_name_or_index: Union[str, Tuple[str, ...]]) -> DataType:
         """ Return DataType for the given column name or index. """
-        return self._sdf.schema[self.column_name_for(column_name_or_index)].dataType
+        return self._sdf.select(self.scol_for(column_name_or_index)).schema[0].dataType
 
     @property
     def sdf(self) -> spark.DataFrame:

databricks/koalas/series.py

@@ -350,7 +350,7 @@ def dtypes(self):
     @property
     def spark_type(self):
         """ Returns the data type as defined by Spark, as a Spark DataType object."""
-        return self.schema.fields[-1].dataType
+        return self._internal.spark_type_for(self._internal.column_index[0])
 
     plot = CachedAccessor("plot", KoalasSeriesPlotMethods)
 
@@ -798,10 +798,10 @@ def astype(self, dtype) -> 'Series':
         return self._with_new_scol(self._scol.cast(spark_type))
 
     def getField(self, name):
-        if not isinstance(self.schema, StructType):
-            raise AttributeError("Not a struct: {}".format(self.schema))
+        if not isinstance(self.spark_type, StructType):
+            raise AttributeError("Not a struct: {}".format(self.spark_type))
         else:
-            fnames = self.schema.fieldNames()
+            fnames = self.spark_type.fieldNames()
             if name not in fnames:
                 raise AttributeError(
                     "Field {} not found, possible values are {}".format(name, ", ".join(fnames)))
@@ -811,11 +811,6 @@ def alias(self, name):
         """An alias for :meth:`Series.rename`."""
         return self.rename(name)
 
-    @property
-    def schema(self) -> StructType:
-        """Return the underlying Spark DataFrame's schema."""
-        return self.to_dataframe()._sdf.schema
-
     @property
     def shape(self):
         """Return a tuple of the shape of the underlying data."""
@@ -4030,10 +4025,10 @@ def __repr__(self):
         return pser.to_string(name=self.name, dtype=self.dtype)
 
     def __dir__(self):
-        if not isinstance(self.schema, StructType):
+        if not isinstance(self.spark_type, StructType):
             fields = []
         else:
-            fields = [f for f in self.schema.fieldNames() if ' ' not in f]
+            fields = [f for f in self.spark_type.fieldNames() if ' ' not in f]
         return super(Series, self).__dir__() + fields
 
     def __iter__(self):

docs/source/reference/series.rst

@@ -26,7 +26,7 @@ Attributes
    Series.dtype
    Series.dtypes
    Series.name
-   Series.schema
+   Series.spark_type
    Series.shape
    Series.size
    Series.empty