drop the hive DB before populating it from scratch

dhp-workflows/dhp-graph-mapper/src/main/java/eu/dnetlib/dhp/graph/SparkGraphImporterJob.java

@@ -27,6 +27,7 @@ public class SparkGraphImporterJob {
         final String inputPath = parser.get("sourcePath");
         final String hiveDbName = parser.get("hive_db_name");
 
+        spark.sql(String.format("DROP DATABASE IF EXISTS %s CASCADE", hiveDbName));
         spark.sql(String.format("CREATE DATABASE IF NOT EXISTS %s", hiveDbName));
 
         // Read the input file and convert it into RDD of serializable object

dhp-workflows/dhp-graph-provision/src/main/java/eu/dnetlib/dhp/graph/model/SortableRelationKey.java

@@ -0,0 +1,4 @@
+package eu.dnetlib.dhp.graph;
+
+public class SortableRelationKey {
+}

dhp-workflows/dhp-graph-provision/src/main/java/eu/dnetlib/dhp/graph/utils/RelationPartitioner.java

@@ -0,0 +1,4 @@
+package eu.dnetlib.dhp.graph.utils;
+
+public class RelationPartitioner {
+}

dhp-workflows/dhp-graph-provision/src/test/java/eu/dnetlib/dhp/graph/GraphJoinerTest.java

@@ -0,0 +1,4 @@
+package eu.dnetlib.dhp.graph;
+
+public class GraphJoinerTest {
+}