[SPARK-31224][SQL] Add view support to SHOW CREATE TABLE

### What changes were proposed in this pull request? For now `SHOW CREATE TABLE` command doesn't support views, but `SHOW CREATE TABLE AS SERDE` supports it. Since the views syntax are the same between Hive DDL and Spark DDL, we should be able to support views in both two commands. This is Hive syntax for creating views: ``` CREATE VIEW [IF NOT EXISTS] [db_name.]view_name [(column_name [COMMENT column_comment], ...) ] [COMMENT view_comment] [TBLPROPERTIES (property_name = property_value, ...)] AS SELECT ...; ``` https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-CreateView This is Spark syntax for creating views: ``` CREATE [OR REPLACE] [[GLOBAL] TEMPORARY] VIEW [IF NOT EXISTS [db_name.]view_name create_view_clauses AS query; ``` https://spark.apache.org/docs/3.0.0-preview/sql-ref-syntax-ddl-create-view.html Looks like it is the same. We could support views in both commands. This patch proposes to add views support to `SHOW CREATE TABLE`. ### Why are the changes needed? To extend the view support of `SHOW CREATE TABLE`, so users can use `SHOW CREATE TABLE` to show Spark DDL for views. ### Does this PR introduce any user-facing change? Yes. `SHOW CREATE TABLE` can be used to show Spark DDL for views. ### How was this patch tested? Unit tests. Closes apache#27984 from viirya/spark-view. Authored-by: Liang-Chi Hsieh <[email protected]> Signed-off-by: Wenchen Fan <[email protected]>
sjincho · Apr 14, 2020 · 98fcdf6 · 98fcdf6
1 parent 13f3247
commit 98fcdf6
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diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala
@@ -1057,6 +1057,42 @@ trait ShowCreateTableCommandBase {
   protected def concatByMultiLines(iter: Iterable[String]): String = {
     iter.mkString("(\n  ", ",\n  ", ")\n")
   }
+
+  protected def showCreateView(metadata: CatalogTable, builder: StringBuilder): Unit = {
+    showViewDataColumns(metadata, builder)
+    showTableComment(metadata, builder)
+    showViewProperties(metadata, builder)
+    showViewText(metadata, builder)
+  }
+
+  private def showViewDataColumns(metadata: CatalogTable, builder: StringBuilder): Unit = {
+    if (metadata.schema.nonEmpty) {
+      val viewColumns = metadata.schema.map { f =>
+        val comment = f.getComment()
+          .map(escapeSingleQuotedString)
+          .map(" COMMENT '" + _ + "'")
+
+        // view columns shouldn't have data type info
+        s"${quoteIdentifier(f.name)}${comment.getOrElse("")}"
+      }
+      builder ++= concatByMultiLines(viewColumns)
+    }
+  }
+
+  private def showViewProperties(metadata: CatalogTable, builder: StringBuilder): Unit = {
+    val viewProps = metadata.properties.filterKeys(!_.startsWith(CatalogTable.VIEW_PREFIX))
+    if (viewProps.nonEmpty) {
+      val props = viewProps.map { case (key, value) =>
+        s"'${escapeSingleQuotedString(key)}' = '${escapeSingleQuotedString(value)}'"
+      }
+
+      builder ++= s"TBLPROPERTIES ${concatByMultiLines(props)}"
+    }
+  }
+
+  private def showViewText(metadata: CatalogTable, builder: StringBuilder): Unit = {
+    builder ++= metadata.viewText.mkString("AS ", "", "\n")
+  }
 }
 
 /**
@@ -1100,21 +1136,33 @@ case class ShowCreateTableCommand(table: TableIdentifier)
           )
         }
 
-        if (tableMetadata.tableType == VIEW) {
-          throw new AnalysisException("Hive view isn't supported by SHOW CREATE TABLE")
-        }
-
         if ("true".equalsIgnoreCase(tableMetadata.properties.getOrElse("transactional", "false"))) {
           throw new AnalysisException(
             "SHOW CREATE TABLE doesn't support transactional Hive table. " +
               s"Please use `SHOW CREATE TABLE ${tableMetadata.identifier} AS SERDE` " +
               "to show Hive DDL instead.")
         }
 
-        convertTableMetadata(tableMetadata)
+        if (tableMetadata.tableType == VIEW) {
+          tableMetadata
+        } else {
+          convertTableMetadata(tableMetadata)
+        }
       }
 
-      val stmt = showCreateDataSourceTable(metadata)
+      val builder = StringBuilder.newBuilder
+
+      val stmt = if (tableMetadata.tableType == VIEW) {
+        builder ++= s"CREATE VIEW ${table.quotedString} "
+        showCreateView(metadata, builder)
+
+        builder.toString()
+      } else {
+        builder ++= s"CREATE TABLE ${table.quotedString} "
+
+        showCreateDataSourceTable(metadata, builder)
+        builder.toString()
+      }
 
       Seq(Row(stmt))
     }
@@ -1194,18 +1242,13 @@ case class ShowCreateTableCommand(table: TableIdentifier)
     }
   }
 
-  private def showCreateDataSourceTable(metadata: CatalogTable): String = {
-    val builder = StringBuilder.newBuilder
-
-    builder ++= s"CREATE TABLE ${table.quotedString} "
+  private def showCreateDataSourceTable(metadata: CatalogTable, builder: StringBuilder): Unit = {
     showDataSourceTableDataColumns(metadata, builder)
     showDataSourceTableOptions(metadata, builder)
     showDataSourceTableNonDataColumns(metadata, builder)
     showTableComment(metadata, builder)
     showTableLocation(metadata, builder)
     showTableProperties(metadata, builder)
-
-    builder.toString()
   }
 }
 
@@ -1264,10 +1307,7 @@ case class ShowCreateTableAsSerdeCommand(table: TableIdentifier)
     builder ++= s"CREATE$tableTypeString ${table.quotedString}"
 
     if (metadata.tableType == VIEW) {
-      showViewDataColumns(metadata, builder)
-      showTableComment(metadata, builder)
-      showViewProperties(metadata, builder)
-      showViewText(metadata, builder)
+      showCreateView(metadata, builder)
     } else {
       showHiveTableHeader(metadata, builder)
       showTableComment(metadata, builder)
@@ -1280,35 +1320,6 @@ case class ShowCreateTableAsSerdeCommand(table: TableIdentifier)
     builder.toString()
   }
 
-  private def showViewDataColumns(metadata: CatalogTable, builder: StringBuilder): Unit = {
-    if (metadata.schema.nonEmpty) {
-      val viewColumns = metadata.schema.map { f =>
-        val comment = f.getComment()
-          .map(escapeSingleQuotedString)
-          .map(" COMMENT '" + _ + "'")
-
-        // view columns shouldn't have data type info
-        s"${quoteIdentifier(f.name)}${comment.getOrElse("")}"
-      }
-      builder ++= concatByMultiLines(viewColumns)
-    }
-  }
-
-  private def showViewProperties(metadata: CatalogTable, builder: StringBuilder): Unit = {
-    val viewProps = metadata.properties.filterKeys(!_.startsWith(CatalogTable.VIEW_PREFIX))
-    if (viewProps.nonEmpty) {
-      val props = viewProps.map { case (key, value) =>
-        s"'${escapeSingleQuotedString(key)}' = '${escapeSingleQuotedString(value)}'"
-      }
-
-      builder ++= s"TBLPROPERTIES ${concatByMultiLines(props)}"
-    }
-  }
-
-  private def showViewText(metadata: CatalogTable, builder: StringBuilder): Unit = {
-    builder ++= metadata.viewText.mkString("AS ", "", "\n")
-  }
-
   private def showHiveTableHeader(metadata: CatalogTable, builder: StringBuilder): Unit = {
     val columns = metadata.schema.filterNot { column =>
       metadata.partitionColumnNames.contains(column.name)

diff --git a/sql/core/src/test/resources/sql-tests/inputs/show-create-table.sql b/sql/core/src/test/resources/sql-tests/inputs/show-create-table.sql
@@ -74,6 +74,9 @@ CREATE VIEW view_SPARK_30302 (aaa, bbb)
 AS SELECT a, b FROM tbl;
 
 SHOW CREATE TABLE view_SPARK_30302 AS SERDE;
+
+SHOW CREATE TABLE view_SPARK_30302;
+
 DROP VIEW view_SPARK_30302;
 
 
@@ -83,6 +86,9 @@ COMMENT 'This is a comment with \'quoted text\' for view'
 AS SELECT a, b FROM tbl;
 
 SHOW CREATE TABLE view_SPARK_30302 AS SERDE;
+
+SHOW CREATE TABLE view_SPARK_30302;
+
 DROP VIEW view_SPARK_30302;
 
 
@@ -92,13 +98,9 @@ TBLPROPERTIES ('a' = '1', 'b' = '2')
 AS SELECT a, b FROM tbl;
 
 SHOW CREATE TABLE view_SPARK_30302 AS SERDE;
-DROP VIEW view_SPARK_30302;
-
--- SHOW CREATE TABLE does not support view
-CREATE VIEW view_SPARK_30302 (aaa, bbb)
-AS SELECT a, b FROM tbl;
 
 SHOW CREATE TABLE view_SPARK_30302;
+
 DROP VIEW view_SPARK_30302;
 
 DROP TABLE tbl;
diff --git a/sql/core/src/test/resources/sql-tests/results/show-create-table.sql.out b/sql/core/src/test/resources/sql-tests/results/show-create-table.sql.out
@@ -301,6 +301,17 @@ CREATE VIEW `default`.`view_SPARK_30302`(
 AS SELECT a, b FROM tbl
 
 
+-- !query
+SHOW CREATE TABLE view_SPARK_30302
+-- !query schema
+struct<createtab_stmt:string>
+-- !query output
+CREATE VIEW `default`.`view_SPARK_30302` (
+  `aaa`,
+  `bbb`)
+AS SELECT a, b FROM tbl
+
+
 -- !query
 DROP VIEW view_SPARK_30302
 -- !query schema
@@ -331,6 +342,18 @@ COMMENT 'This is a comment with \'quoted text\' for view'
 AS SELECT a, b FROM tbl
 
 
+-- !query
+SHOW CREATE TABLE view_SPARK_30302
+-- !query schema
+struct<createtab_stmt:string>
+-- !query output
+CREATE VIEW `default`.`view_SPARK_30302` (
+  `aaa` COMMENT 'comment with \'quoted text\' for aaa',
+  `bbb`)
+COMMENT 'This is a comment with \'quoted text\' for view'
+AS SELECT a, b FROM tbl
+
+
 -- !query
 DROP VIEW view_SPARK_30302
 -- !query schema
@@ -363,30 +386,18 @@ TBLPROPERTIES (
 AS SELECT a, b FROM tbl
 
 
--- !query
-DROP VIEW view_SPARK_30302
--- !query schema
-struct<>
--- !query output
-
-
-
--- !query
-CREATE VIEW view_SPARK_30302 (aaa, bbb)
-AS SELECT a, b FROM tbl
--- !query schema
-struct<>
--- !query output
-
-
-
 -- !query
 SHOW CREATE TABLE view_SPARK_30302
 -- !query schema
-struct<>
+struct<createtab_stmt:string>
 -- !query output
-org.apache.spark.sql.AnalysisException
-Hive view isn't supported by SHOW CREATE TABLE;
+CREATE VIEW `default`.`view_SPARK_30302` (
+  `aaa`,
+  `bbb`)
+TBLPROPERTIES (
+  'a' = '1',
+  'b' = '2')
+AS SELECT a, b FROM tbl
 
 
 -- !query

diff --git a/sql/core/src/test/scala/org/apache/spark/sql/ShowCreateTableSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/ShowCreateTableSuite.scala
@@ -188,18 +188,26 @@ abstract class ShowCreateTableSuite extends QueryTest with SQLTestUtils {
     if (result.length > 1) result(0) + result(1) else result.head
   }
 
-  protected def checkCreateTable(table: String): Unit = {
-    checkCreateTableOrView(TableIdentifier(table, Some("default")), "TABLE")
+  protected def checkCreateTable(table: String, serde: Boolean = false): Unit = {
+    checkCreateTableOrView(TableIdentifier(table, Some("default")), "TABLE", serde)
   }
 
-  protected def checkCreateView(table: String): Unit = {
-    checkCreateTableOrView(TableIdentifier(table, Some("default")), "VIEW")
+  protected def checkCreateView(table: String, serde: Boolean = false): Unit = {
+    checkCreateTableOrView(TableIdentifier(table, Some("default")), "VIEW", serde)
   }
 
-  private def checkCreateTableOrView(table: TableIdentifier, checkType: String): Unit = {
+  protected def checkCreateTableOrView(
+      table: TableIdentifier,
+      checkType: String,
+      serde: Boolean): Unit = {
     val db = table.database.getOrElse("default")
     val expected = spark.sharedState.externalCatalog.getTable(db, table.table)
-    val shownDDL = sql(s"SHOW CREATE TABLE ${table.quotedString}").head().getString(0)
+    val shownDDL = if (serde) {
+      sql(s"SHOW CREATE TABLE ${table.quotedString} AS SERDE").head().getString(0)
+    } else {
+      sql(s"SHOW CREATE TABLE ${table.quotedString}").head().getString(0)
+    }
+
     sql(s"DROP $checkType ${table.quotedString}")
 
     try {