[SPARK-22016][SQL] Add HiveDialect for JDBC connection to Hive

sql/core/src/main/scala/org/apache/spark/sql/jdbc/HiveDialect.scala

@@ -0,0 +1,26 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.jdbc
+
+object HiveDialect extends JdbcDialect {
+
+  override def canHandle(url: String): Boolean = url.startsWith("jdbc:hive2")
+
+  override def quoteIdentifier(colName: String): String = s"`$colName`"
+
+}

sql/core/src/main/scala/org/apache/spark/sql/jdbc/JdbcDialects.scala

@@ -200,6 +200,7 @@ object JdbcDialects {
   registerDialect(DerbyDialect)
   registerDialect(OracleDialect)
   registerDialect(TeradataDialect)
+  registerDialect(HiveDialect)
 
   /**
    * Fetch the JdbcDialect class corresponding to a given database url.

sql/core/src/test/scala/org/apache/spark/sql/jdbc/JDBCSuite.scala

@@ -1100,9 +1100,19 @@ class JDBCSuite extends SparkFunSuite
          |OPTIONS (url '$urlWithUserAndPass',
          |dbtable '(SELECT NVL(@MYTESTVAR1, -1), NVL(@MYTESTVAR2, -1))',
          |sessionInitStatement 'SET @MYTESTVAR1 21519; SET @MYTESTVAR2 1234')
-       """.stripMargin)
+      """.stripMargin)
 
-      val df3 = sql("SELECT * FROM test_sessionInitStatement")
-      assert(df3.collect() === Array(Row(21519, 1234)))
-    }
+    val df3 = sql("SELECT * FROM test_sessionInitStatement")
+    assert(df3.collect() === Array(Row(21519, 1234)))
+  }
+
+  test("Hive dialect registration") {
+    assert(JdbcDialects.get("jdbc:hive2://127.0.0.1/db") == HiveDialect)
+  }
+
+  test("Hive dialect quoted identifier") {
+    val dialect = JdbcDialects.get("jdbc:hive2://127.0.0.1/db")
+    val quotedIdentifier = dialect.quoteIdentifier("a_column")
+    assert(quotedIdentifier == "`a_column`")
+  }
 }