[SPARK-19539][SQL] Block duplicate temp table during creation

## What changes were proposed in this pull request?
Current `CREATE TEMPORARY TABLE ... ` is deprecated and recommend users to use `CREATE TEMPORARY VIEW ...` And it does not support `IF NOT EXISTS `clause. However, if there is an existing temporary view defined, it is possible to unintentionally replace this existing view by issuing `CREATE TEMPORARY TABLE ...`  with the same table/view name.

This PR is to disallow `CREATE TEMPORARY TABLE ...` with an existing view name.
Under the cover, `CREATE TEMPORARY TABLE ...` will be changed to create temporary view, however, passing in a flag `replace=false`, instead of currently `true`. So when creating temporary view under the cover, if there is existing view with the same name, the operation will be blocked.

## How was this patch tested?
New unit test case is added and updated some existing test cases to adapt the new behavior

Author: Xin Wu <xinwu@us.ibm.com>

Closes #16878 from xwu0226/block_duplicate_temp_table.

2 files changed, 13 insertions, 13 deletions

diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveCommandSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveCommandSuite.scala
index 8fda1c5875..6937e97a47 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveCommandSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveCommandSuite.scala
@@ -148,8 +148,8 @@ class HiveCommandSuite extends QueryTest with SQLTestUtils with TestHiveSingleto
     withTempView("parquet_temp") {
       sql(
         """
-          |CREATE TEMPORARY TABLE parquet_temp (c1 INT, c2 STRING)
-          |USING org.apache.spark.sql.parquet.DefaultSource
+         |CREATE TEMPORARY VIEW parquet_temp (c1 INT, c2 STRING)
+         |USING org.apache.spark.sql.parquet.DefaultSource
         """.stripMargin)
 
       // An empty sequence of row is returned for session temporary table.
@@ -401,8 +401,8 @@ class HiveCommandSuite extends QueryTest with SQLTestUtils with TestHiveSingleto
     withTempView("parquet_temp") {
       sql(
         """
-          |CREATE TEMPORARY TABLE parquet_temp (c1 INT, c2 STRING)
-          |USING org.apache.spark.sql.parquet.DefaultSource
+         |CREATE TEMPORARY VIEW parquet_temp (c1 INT, c2 STRING)
+         |USING org.apache.spark.sql.parquet.DefaultSource
         """.stripMargin)
       // An empty sequence of row is returned for session temporary table.
       intercept[NoSuchTableException] {
diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala
index 20f30e48ab..faed8b5046 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/SQLQuerySuite.scala
@@ -1290,7 +1290,7 @@ class SQLQuerySuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
         "interval 4 minutes 59 seconds 889 milliseconds 987 microseconds")))
   }
 
-  test("specifying database name for a temporary table is not allowed") {
+  test("specifying database name for a temporary view is not allowed") {
     withTempPath { dir =>
       val path = dir.toURI.toString
       val df = sparkContext.parallelize(1 to 10).map(i => (i, i.toString)).toDF("num", "str")
@@ -1303,23 +1303,23 @@ class SQLQuerySuite extends QueryTest with SQLTestUtils with TestHiveSingleton {
       intercept[AnalysisException] {
         spark.sql(
           s"""
-          |CREATE TEMPORARY TABLE db.t
-          |USING parquet
-          |OPTIONS (
-          |  path '$path'
-          |)
-        """.stripMargin)
+            |CREATE TEMPORARY VIEW db.t
+            |USING parquet
+            |OPTIONS (
+            |  path '$path'
+            |)
+           """.stripMargin)
       }
 
       // If you use backticks to quote the name then it's OK.
       spark.sql(
         s"""
-          |CREATE TEMPORARY TABLE `db.t`
+          |CREATE TEMPORARY VIEW `db.t`
           |USING parquet
           |OPTIONS (
           |  path '$path'
           |)
-        """.stripMargin)
+         """.stripMargin)
       checkAnswer(spark.table("`db.t`"), df)
     }
   }