Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/12362#discussion_r59677375
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/command/tables.scala ---
@@ -17,9 +17,45 @@
package org.apache.spark.sql.execution.command
-import org.apache.spark.sql.{Row, SQLContext}
+import org.apache.spark.sql.{AnalysisException, Row, SQLContext}
import org.apache.spark.sql.catalyst.TableIdentifier
-import org.apache.spark.sql.catalyst.catalog.CatalogTable
+import org.apache.spark.sql.catalyst.catalog.{CatalogTable,
CatalogTableType}
+
+/**
+ * A command to create a table with the same definition of the given
existing table.
+ *
+ * The syntax of using this command in SQL is:
+ * {{{
+ * CREATE TABLE [IF NOT EXISTS] [db_name.]table_name
+ * LIKE [other_db_name.]existing_table_name
+ * }}}
+ */
+case class CreateTableLike(
+ targetTable: TableIdentifier,
+ sourceTable: TableIdentifier,
+ ifNotExists: Boolean) extends RunnableCommand {
+
+ override def run(sqlContext: SQLContext): Seq[Row] = {
+ val catalog = sqlContext.sessionState.catalog
+ if (!catalog.tableExists(sourceTable)) {
+ throw new AnalysisException(
+ s"Source table in CREATE TABLE LIKE does not exist:
'$sourceTable'")
+ }
+ if (catalog.isTemporaryTable(sourceTable)) {
+ throw new AnalysisException(
+ s"Source table in CREATE TABLE LIKE cannot be temporary:
'$sourceTable'")
+ }
+
+ val tableToCreate = catalog.getTableMetadata(sourceTable).copy(
--- End diff --
instead of doing a copy and change some variables that we need to update,
how about we create a new `CatalogTable` and put the stuff that we need to
retain from the source table? Then it's more clear that what we retained for
the `CREATE TABLE LIKE` command.
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