Can't run saveAsTable with database name

The function "saveAsTable" with database and table name is running via 1.6.2 successfully. But when I upgrade 2.0, it's got the error. There are my code and error message. Can you help me?

conf/hive-site.xml
<property>
<name>hive.metastore.uris</name>
<value>thrift://localhost:9083</value>
</property>

val spark = SparkSession.builder().appName("SparkHive").enableHiveSupport().getOrCreate()

import spark.implicits._
import spark.sql

val source = sql("select * from sample.sample")

source.createOrReplaceTempView("test")
source.collect.foreach

val target = sql("select key, 'Spark' as value from test")

println(target.count())

target.write.mode(SaveMode.Append).saveAsTable("sample.sample")

spark.stop()

Exception in thread "main" org.apache.spark.sql.AnalysisException: Saving data in MetastoreRelation sample, sample
is not supported.;
at org.apache.spark.sql.execution.command.CreateDataSourceTableAsSelectCommand.run(createDataSourceTables.scala:218)
at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult$lzycompute(commands.scala:60)
at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult(commands.scala:58)
at org.apache.spark.sql.execution.command.ExecutedCommandExec.doExecute(commands.scala:74)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:115)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$execute$1.apply(SparkPlan.scala:115)
at org.apache.spark.sql.execution.SparkPlan$$anonfun$executeQuery$1.apply(SparkPlan.scala:136)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
at org.apache.spark.sql.execution.SparkPlan.executeQuery(SparkPlan.scala:133)
at org.apache.spark.sql.execution.SparkPlan.execute(SparkPlan.scala:114)
at org.apache.spark.sql.execution.QueryExecution.toRdd$lzycompute(QueryExecution.scala:86)
at org.apache.spark.sql.execution.QueryExecution.toRdd(QueryExecution.scala:86)
at org.apache.spark.sql.DataFrameWriter.saveAsTable(DataFrameWriter.scala:378)
at org.apache.spark.sql.DataFrameWriter.saveAsTable(DataFrameWriter.scala:354)
at com.newtouch.sample.SparkHive$.main(SparkHive.scala:25)
at com.newtouch.sample.SparkHive.main(SparkHive.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:729)
at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:185)
at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:210)
at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:124)
at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)