[SPARK-17338][SQL][FOLLOW-UP] add global temp view

## What changes were proposed in this pull request?

address post hoc review comments for https://github.com/apache/spark/pull/14897

## How was this patch tested?

N/A

Author: Wenchen Fan <wenchen@databricks.com>

Closes #15424 from cloud-fan/global-temp-view.

3 files changed, 10 insertions, 10 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala b/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala
index 30349ba3cb..a7a84730a6 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/Dataset.scala
@@ -2494,7 +2494,7 @@ class Dataset[T] private[sql](
    * preserved database `_global_temp`, and we must use the qualified name to refer a global temp
    * view, e.g. `SELECT * FROM _global_temp.view1`.
    *
-   * @throws TempTableAlreadyExistsException if the view name already exists
+   * @throws AnalysisException if the view name already exists
    *
    * @group basic
    * @since 2.1.0
@@ -2508,12 +2508,7 @@ class Dataset[T] private[sql](
       viewName: String,
       replace: Boolean,
       global: Boolean): CreateViewCommand = {
-    val viewType = if (global) {
-      GlobalTempView
-    } else {
-      LocalTempView
-    }
-
+    val viewType = if (global) GlobalTempView else LocalTempView
     CreateViewCommand(
       name = sparkSession.sessionState.sqlParser.parseTableIdentifier(viewName),
       userSpecifiedColumns = Nil,
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala b/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala
index 717fb29190..18cba8ce28 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/catalog/Catalog.scala
@@ -269,10 +269,14 @@ abstract class Catalog {
    * created it, i.e. it will be automatically dropped when the session terminates. It's not
    * tied to any databases, i.e. we can't use `db1.view1` to reference a local temporary view.
    *
+   * Note that, the return type of this method was Unit in Spark 2.0, but changed to Boolean
+   * in Spark 2.1.
+   *
    * @param viewName the name of the view to be dropped.
+   * @return true if the view is dropped successfully, false otherwise.
    * @since 2.0.0
    */
-  def dropTempView(viewName: String): Unit
+  def dropTempView(viewName: String): Boolean
 
   /**
    * Drops the global temporary view with the given view name in the catalog.
@@ -284,6 +288,7 @@ abstract class Catalog {
    * view, e.g. `SELECT * FROM _global_temp.view1`.
    *
    * @param viewName the name of the view to be dropped.
+   * @return true if the view is dropped successfully, false otherwise.
    * @since 2.1.0
    */
   def dropGlobalTempView(viewName: String): Boolean
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala b/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala
index c05bda3f1b..f6c297e91b 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/internal/CatalogImpl.scala
@@ -371,8 +371,8 @@ class CatalogImpl(sparkSession: SparkSession) extends Catalog {
    * @group ddl_ops
    * @since 2.0.0
    */
-  override def dropTempView(viewName: String): Unit = {
-    sparkSession.sessionState.catalog.getTempView(viewName).foreach { tempView =>
+  override def dropTempView(viewName: String): Boolean = {
+    sparkSession.sessionState.catalog.getTempView(viewName).exists { tempView =>
       sparkSession.sharedState.cacheManager.uncacheQuery(Dataset.ofRows(sparkSession, tempView))
       sessionCatalog.dropTempView(viewName)
     }