Added baseRelationToSchemaRDD back.

Author: rxin

sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala

@@ -37,7 +37,7 @@ import org.apache.spark.sql.catalyst.rules.RuleExecutor
 import org.apache.spark.sql.execution._
 import org.apache.spark.sql.json._
 import org.apache.spark.sql.parquet.ParquetRelation
-import org.apache.spark.sql.sources.{DDLParser, DataSourceStrategy}
+import org.apache.spark.sql.sources.{LogicalRelation, BaseRelation, DDLParser, DataSourceStrategy}
 import org.apache.spark.sql.types._
 
 /**
@@ -130,6 +130,13 @@ class SQLContext(@transient val sparkContext: SparkContext)
     new SchemaRDD(this, LogicalRDD(attributeSeq, rowRDD)(self))
   }
 
+  /**
+   * Convert a [[BaseRelation]] created for external data sources into a [[SchemaRDD]].
+   */
+  def baseRelationToSchemaRDD(baseRelation: BaseRelation): SchemaRDD = {
+    new SchemaRDD(this, LogicalRelation(baseRelation))
+  }
+
   /**
    * :: DeveloperApi ::
    * Creates a [[SchemaRDD]] from an [[RDD]] containing [[Row]]s by applying a schema to this RDD.