diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/DocumentRDDFunctions.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/DocumentRDDFunctions.scala
index 5d227f8f23b8a..3c58fc6ba2bd9 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/DocumentRDDFunctions.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/DocumentRDDFunctions.scala
@@ -8,7 +8,6 @@ import com.mapr.db.spark.configuration.SerializableConfiguration
 import com.mapr.db.spark.dbclient.DBClient
 import com.mapr.db.spark.utils.{LoggingTrait, MapRDBUtils}
 import com.mapr.db.spark.writers._
-
 import org.apache.hadoop.conf.Configuration
 import org.ojai.{Document, DocumentConstants, Value}
 import org.ojai.store.DocumentMutation
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBBaseRDD.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBBaseRDD.scala
index 08821b0bcbc62..441d292bbfe8e 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBBaseRDD.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBBaseRDD.scala
@@ -1,15 +1,16 @@
 /* Copyright (c) 2015 & onwards. MapR Tech, Inc., All rights reserved */
 package com.mapr.db.spark.RDD
 
+import scala.language.existentials
+import scala.reflect.ClassTag
+
 import com.mapr.db.exceptions.DBException
 import com.mapr.db.spark.condition.{DBQueryCondition, Predicate}
 import com.mapr.db.spark.dbclient.DBClient
-import org.apache.spark.rdd.RDD
+import org.ojai.store.QueryCondition
 
-import scala.language.existentials
-import scala.reflect.ClassTag
+import org.apache.spark.rdd.RDD
 import org.apache.spark.SparkContext
-import org.ojai.store.QueryCondition
 
 private[spark] abstract class MapRDBBaseRDD[T: ClassTag](
     @transient val sc: SparkContext,
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBTableScanRDD.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBTableScanRDD.scala
index b9de182d9f7ab..bd3920a02db79 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBTableScanRDD.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/MapRDBTableScanRDD.scala
@@ -4,7 +4,6 @@ package com.mapr.db.spark.RDD
 import scala.language.existentials
 import scala.reflect.ClassTag
 import scala.reflect.runtime.universe._
-
 import com.mapr.db.impl.{ConditionImpl, IdCodec}
 import com.mapr.db.spark.RDD.partition.MaprDBPartition
 import com.mapr.db.spark.RDD.partitioner.MapRDBPartitioner
@@ -14,14 +13,10 @@ import com.mapr.db.spark.dbclient.DBClient
 import com.mapr.db.spark.impl.OJAIDocument
 import com.mapr.db.spark.utils.DefaultClass.DefaultType
 import com.mapr.db.spark.utils.MapRSpark
-
 import org.ojai.{Document, Value}
-
 import org.apache.spark.{Partition, Partitioner, SparkContext, TaskContext}
 import org.apache.spark.broadcast.Broadcast
-import org.apache.spark.sql.SparkSession
-
-
+import org.apache.spark.sql.{DataFrame, SparkSession}
 
 private[spark] class MapRDBTableScanRDD[T: ClassTag](
     @transient sparkSession: SparkSession,
@@ -36,9 +31,9 @@ private[spark] class MapRDBTableScanRDD[T: ClassTag](
 
   @transient private lazy val table = DBClient().getTable(tableName)
   @transient private lazy val tabletinfos =
-    if (condition == null || condition.condition.isEmpty)
+    if (condition == null || condition.condition.isEmpty) {
       DBClient().getTabletInfos(tableName)
-    else DBClient().getTabletInfos(tableName, condition.condition)
+    } else DBClient().getTabletInfos(tableName, condition.condition)
   @transient private lazy val getSplits: Seq[Value] = {
     val keys = tabletinfos.map(
       tableinfo =>
@@ -52,18 +47,18 @@ private[spark] class MapRDBTableScanRDD[T: ClassTag](
   }
 
   private def getPartitioner: Partitioner = {
-    if (getSplits.isEmpty)
-      return null
-    if (getSplits(0).getType == Value.Type.STRING) {
-      return MapRDBPartitioner(getSplits.map(_.getString))
+    if (getSplits.isEmpty) {
+      null
+    } else if (getSplits(0).getType == Value.Type.STRING) {
+      MapRDBPartitioner(getSplits.map(_.getString))
     } else {
-      return MapRDBPartitioner(getSplits.map(_.getBinary))
+      MapRDBPartitioner(getSplits.map(_.getBinary))
     }
   }
 
-  def toDF[T <: Product: TypeTag]() = maprspark[T]()
+  def toDF[T <: Product: TypeTag](): DataFrame = maprspark[T]()
 
-  def maprspark[T <: Product: TypeTag]() = {
+  def maprspark[T <: Product: TypeTag](): DataFrame = {
     MapRSpark.builder
       .sparkSession(sparkSession)
       .configuration()
@@ -89,7 +84,7 @@ private[spark] class MapRDBTableScanRDD[T: ClassTag](
                       DBQueryCondition(tabcond)).asInstanceOf[Partition]
     })
     logDebug("Partitions for the table:" + tableName + " are " + splits)
-    return splits.toArray
+    splits.toArray
   }
 
   override def getPreferredLocations(split: Partition): Seq[String] = {
@@ -125,8 +120,9 @@ private[spark] class MapRDBTableScanRDD[T: ClassTag](
     if (columns != null) {
       logDebug("Columns projected from table:" + columns)
       itrs = table.find(combinedCond.build(), columns.toArray: _*).iterator()
-    } else
+    } else {
       itrs = table.find(combinedCond.build()).iterator()
+    }
     val ojaiCursor = reqType.getValue(itrs, beanClass)
 
     context.addTaskCompletionListener((ctx: TaskContext) => {
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/partition/MapRDBPartition.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/partition/MapRDBPartition.scala
index f1bb4badccc37..3a81479c5d69a 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/partition/MapRDBPartition.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/RDD/partition/MapRDBPartition.scala
@@ -1,8 +1,9 @@
 /* Copyright (c) 2015 & onwards. MapR Tech, Inc., All rights reserved */
 package com.mapr.db.spark.RDD.partition
 
-import org.apache.spark.Partition
 import com.mapr.db.spark.condition.DBQueryCondition
+
+import org.apache.spark.Partition
 /**
   * An identifier for a partition in a MapRTableScanRDD.
   *
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/sql/DefaultSource.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/sql/DefaultSource.scala
index c28af39360183..3be938a2f2058 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/sql/DefaultSource.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/sql/DefaultSource.scala
@@ -8,12 +8,12 @@ import com.mapr.db.impl.ConditionImpl
 import com.mapr.db.spark.dbclient.DBClient
 import com.mapr.db.spark.utils.MapRSpark
 import org.ojai.DocumentConstants
+import org.ojai.store.QueryCondition
 
-import org.apache.spark.sql.{DataFrame, SQLContext, SaveMode}
+import org.apache.spark.sql.{DataFrame, SaveMode, SQLContext}
 import org.apache.spark.sql.sources._
-import org.apache.spark.sql.types.StructType
+import org.apache.spark.sql.types.{StructField, StructType}
 import org.apache.spark.sql.SaveMode._
-import org.ojai.store.QueryCondition
 
 class DefaultSource
     extends DataSourceRegister
@@ -156,7 +156,6 @@ class DefaultSource
     val failureOnConflict = failOnConflict.toBoolean
 
     val rdd = MapRSpark.builder
-      .sparkContext(sqlContext.sparkContext)
       .sparkSession(sqlContext.sparkSession)
       .configuration()
       .setTable(tableName.get)
@@ -165,15 +164,21 @@ class DefaultSource
       .build
       .toRDD(null)
 
-    val schema: StructType = userSchema match {
+    val schema: StructType = makeSchemaNullable(userSchema match {
       case Some(s) => s
       case None =>
         GenerateSchema(
           rdd,
           sampleSize.map(_.toDouble).getOrElse(GenerateSchema.SAMPLE_SIZE),
           failureOnConflict)
-    }
+    })
 
     MapRDBRelation(tableName.get, schema, rdd, Operation)(sqlContext)
   }
+
+  private def makeSchemaNullable(schema: StructType): StructType = {
+    StructType(schema.map(field => {
+      StructField(field.name, field.dataType, nullable = true, field.metadata  )
+    }))
+  }
 }
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/sql/GenerateSchema.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/sql/GenerateSchema.scala
index 81962cc240f55..17217e5d6b410 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/sql/GenerateSchema.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/sql/GenerateSchema.scala
@@ -1,25 +1,25 @@
 /* Copyright (c) 2015 & onwards. MapR Tech, Inc., All rights reserved */
 package com.mapr.db.spark.sql
 
-import com.mapr.db.spark.RDD.MapRDBBaseRDD
-import com.mapr.db.spark.impl.OJAIDocument
-import com.mapr.db.spark.utils.MapRSpark
-import org.apache.spark.rdd.RDD
-import org.apache.spark.sql.types.{DataType, DataTypes, StructField, StructType}
-import org.ojai.DocumentReader
+import java.util.Arrays.sort
+import java.util.Comparator
 
 import scala.reflect.runtime.universe._
 import scala.Array._
-import java.util.Arrays.sort
-import java.util.Comparator
 
 import com.mapr.db.spark.exceptions.SchemaMappingException
+import com.mapr.db.spark.RDD.MapRDBBaseRDD
+import com.mapr.db.spark.impl.OJAIDocument
+import com.mapr.db.spark.utils.MapRSpark
+import org.ojai.DocumentReader
+
+import org.apache.spark.rdd.RDD
 import org.apache.spark.SparkContext
 import org.apache.spark.sql.catalyst.{JavaTypeInference, ScalaReflection}
 import org.apache.spark.sql.catalyst.analysis.TypeCoercion
 import org.apache.spark.sql.types._
+import org.apache.spark.sql.types.{DataType, DataTypes, StructField, StructType}
 
-import scala.annotation.switch
 
 object GenerateSchema {
 
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/streaming/DStreamFunctions.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/streaming/DStreamFunctions.scala
index 664358674ba45..1eaa81e307081 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/streaming/DStreamFunctions.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/streaming/DStreamFunctions.scala
@@ -1,13 +1,14 @@
 /* Copyright (c) 2015 & onwards. MapR Tech, Inc., All rights reserved */
 package com.mapr.db.spark.streaming
 
+import com.mapr.db.spark._
 import com.mapr.db.spark.dbclient.DBClient
 import com.mapr.db.spark.utils.LoggingTrait
-import org.apache.spark.SparkContext
-import org.apache.spark.streaming.dstream.DStream
-import org.ojai.DocumentConstants
-import com.mapr.db.spark._
 import com.mapr.db.spark.writers.OJAIValue
+import org.ojai.DocumentConstants
+
+import org.apache.spark.streaming.dstream.DStream
+import org.apache.spark.SparkContext
 
 class DStreamFunctions[T](dStream: DStream[T])(implicit fv: OJAIValue[T])
     extends Serializable
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBBinaryValue.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBBinaryValue.scala
index 3160cbf4158b8..fe0a322c5a926 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBBinaryValue.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBBinaryValue.scala
@@ -3,6 +3,7 @@ package com.mapr.db.spark.types
 
 import java.io.{Externalizable, ObjectInput, ObjectOutput}
 import java.nio.{ByteBuffer, ByteOrder}
+
 import com.mapr.db.impl.IdCodec
 import com.mapr.db.spark.utils.MapRDBUtils
 import com.mapr.db.util.ByteBufs
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBMapValue.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBMapValue.scala
index 37176f02bad26..9a306a15ea333 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBMapValue.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/types/DBMapValue.scala
@@ -5,9 +5,10 @@ import java.io.{Externalizable, ObjectInput, ObjectOutput}
 import java.nio._
 import java.util
 
-import scala.language.implicitConversions
 import scala.collection.JavaConverters._
 import scala.collection.MapLike
+import scala.language.implicitConversions
+
 import com.mapr.db.rowcol.RowcolCodec
 import com.mapr.db.spark.dbclient.DBClient
 import com.mapr.db.spark.utils.MapRDBUtils
diff --git a/external/maprdb/src/main/scala/com/mapr/db/spark/writers/BulkTableWriter.scala b/external/maprdb/src/main/scala/com/mapr/db/spark/writers/BulkTableWriter.scala
index a24d20c0c28dc..1bcbd9e109657 100644
--- a/external/maprdb/src/main/scala/com/mapr/db/spark/writers/BulkTableWriter.scala
+++ b/external/maprdb/src/main/scala/com/mapr/db/spark/writers/BulkTableWriter.scala
@@ -2,9 +2,10 @@
 package com.mapr.db.spark.writers
 
 import java.nio.ByteBuffer
-import org.ojai.Document
+
 import com.mapr.db.mapreduce.BulkLoadRecordWriter
 import com.mapr.db.rowcol.DBValueBuilderImpl
+import org.ojai.Document
 
 private[spark] case class BulkTableWriter(@transient table: BulkLoadRecordWriter) extends Writer {