/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.spark.sql.jdbc

import java.math.BigDecimal
import java.sql.{Connection, Date, Timestamp}
import java.time.{Duration, Period}
import java.util.{Properties, TimeZone}

import org.apache.spark.sql.{DataFrame, Row, SaveMode}
import org.apache.spark.sql.catalyst.util.CharVarcharUtils
import org.apache.spark.sql.catalyst.util.DateTimeTestUtils._
import org.apache.spark.sql.execution.{RowDataSourceScanExec, WholeStageCodegenExec}
import org.apache.spark.sql.execution.datasources.LogicalRelationWithTable
import org.apache.spark.sql.execution.datasources.jdbc.{JDBCPartition, JDBCRelation}
import org.apache.spark.sql.internal.SQLConf
import org.apache.spark.sql.test.SharedSparkSession
import org.apache.spark.sql.types._
import org.apache.spark.tags.DockerTest

/**
 * The following are the steps to test this:
 *
 * 1. Choose to use a prebuilt image or build Oracle database in a container
 *    - The documentation on how to build Oracle RDBMS in a container is at
 *      https://github.com/oracle/docker-images/blob/master/OracleDatabase/SingleInstance/README.md
 *    - Official Oracle container images can be found at https://container-registry.oracle.com
 *    - Trustable and streamlined Oracle Database Free images can be found on Docker Hub at
 *      https://hub.docker.com/r/gvenzl/oracle-free
 *      see also https://github.com/gvenzl/oci-oracle-free
 * 2. Run: export ORACLE_DOCKER_IMAGE_NAME=image_you_want_to_use_for_testing
 *    - Example: export ORACLE_DOCKER_IMAGE_NAME=gvenzl/oracle-free:latest
 * 3. Run: export ENABLE_DOCKER_INTEGRATION_TESTS=1
 * 4. Start docker: sudo service docker start
 *    - Optionally, docker pull $ORACLE_DOCKER_IMAGE_NAME
 * 5. Run Spark integration tests for Oracle with: ./build/sbt -Pdocker-integration-tests
 *    "docker-integration-tests/testOnly org.apache.spark.sql.jdbc.OracleIntegrationSuite"
 *
 * A sequence of commands to build the Oracle Database Free container image:
 *  $ git clone https://github.com/oracle/docker-images.git
 *  $ cd docker-images/OracleDatabase/SingleInstance/dockerfiles
 *  $ ./buildContainerImage.sh -v 23.4.0 -f
 *  $ export ORACLE_DOCKER_IMAGE_NAME=oracle/database:23.4.0-free
 *
 * This procedure has been validated with Oracle Database Free version 23.4.0,
 * and with Oracle Express Edition versions 18.4.0 and 21.4.0
 */
@DockerTest
class OracleIntegrationSuite extends DockerJDBCIntegrationSuite with SharedSparkSession {
  import testImplicits._

  override val db = new OracleDatabaseOnDocker

  private val rsOfTsWithTimezone = Seq(
    Row(BigDecimal.valueOf(1), new Timestamp(944046000000L)),
    Row(BigDecimal.valueOf(2), new Timestamp(944078400000L))
  )

  override def dataPreparation(conn: Connection): Unit = {
    // In 18.4.0 Express Edition auto commit is enabled by default.
    conn.setAutoCommit(false)
    conn.prepareStatement("CREATE TABLE datetime (id NUMBER(10), d DATE, t TIMESTAMP)")
      .executeUpdate()
    conn.prepareStatement(
      """INSERT INTO datetime VALUES
        |(1, {d '1991-11-09'}, {ts '1996-01-01 01:23:45'})
      """.stripMargin.replaceAll("\n", " ")).executeUpdate()
    conn.commit()

    conn.prepareStatement(
      "CREATE TABLE ts_with_timezone (id NUMBER(10), t TIMESTAMP WITH TIME ZONE)").executeUpdate()
    conn.prepareStatement(
      "INSERT INTO ts_with_timezone VALUES " +
        "(1, to_timestamp_tz('1999-12-01 11:00:00 UTC','YYYY-MM-DD HH:MI:SS TZR'))").executeUpdate()
    conn.prepareStatement(
      "INSERT INTO ts_with_timezone VALUES " +
        "(2, to_timestamp_tz('1999-12-01 12:00:00 PST','YYYY-MM-DD HH:MI:SS TZR'))").executeUpdate()
    conn.commit()

    conn.prepareStatement(
      "CREATE TABLE tableWithCustomSchema (id NUMBER, n1 NUMBER(1), n2 NUMBER(1))").executeUpdate()
    conn.prepareStatement(
      "INSERT INTO tableWithCustomSchema values(12312321321321312312312312123, 1, 0)")
      .executeUpdate()
    conn.commit()

    sql(
      s"""
        |CREATE TEMPORARY VIEW datetime
        |USING org.apache.spark.sql.jdbc
        |OPTIONS (url '$jdbcUrl', dbTable 'datetime', oracle.jdbc.mapDateToTimestamp 'false')
      """.stripMargin.replaceAll("\n", " "))

    conn.prepareStatement("CREATE TABLE datetime1 (id NUMBER(10), d DATE, t TIMESTAMP)")
      .executeUpdate()
    conn.commit()

    sql(
      s"""
        |CREATE TEMPORARY VIEW datetime1
        |USING org.apache.spark.sql.jdbc
        |OPTIONS (url '$jdbcUrl', dbTable 'datetime1', oracle.jdbc.mapDateToTimestamp 'false')
      """.stripMargin.replaceAll("\n", " "))


    conn.prepareStatement("CREATE TABLE numerics (b DECIMAL(1), f DECIMAL(3, 2), i DECIMAL(10)," +
        "n NUMBER(7,-2))")
      .executeUpdate()
    conn.prepareStatement(
      "INSERT INTO numerics VALUES (4, 1.23, 9999999999, 7456123.89)").executeUpdate()
    conn.commit()

    conn.prepareStatement("CREATE TABLE oracle_types (d BINARY_DOUBLE, f BINARY_FLOAT)")
      .executeUpdate()
    conn.commit()

    conn.prepareStatement("CREATE TABLE datetimePartitionTest (id NUMBER(10), d DATE, t TIMESTAMP)")
      .executeUpdate()
    conn.prepareStatement(
      """INSERT INTO datetimePartitionTest VALUES
        |(1, {d '2018-07-06'}, {ts '2018-07-06 05:50:00'})
      """.stripMargin.replaceAll("\n", " ")).executeUpdate()
    conn.prepareStatement(
      """INSERT INTO datetimePartitionTest VALUES
        |(2, {d '2018-07-06'}, {ts '2018-07-06 08:10:08'})
      """.stripMargin.replaceAll("\n", " ")).executeUpdate()
    conn.prepareStatement(
      """INSERT INTO datetimePartitionTest VALUES
        |(3, {d '2018-07-08'}, {ts '2018-07-08 13:32:01'})
      """.stripMargin.replaceAll("\n", " ")).executeUpdate()
    conn.prepareStatement(
      """INSERT INTO datetimePartitionTest VALUES
        |(4, {d '2018-07-12'}, {ts '2018-07-12 09:51:15'})
      """.stripMargin.replaceAll("\n", " ")).executeUpdate()
    conn.commit()

    conn.prepareStatement("CREATE TABLE test_ltz(t TIMESTAMP WITH LOCAL TIME ZONE)")
      .executeUpdate()
    conn.prepareStatement(
      "INSERT INTO test_ltz (t) VALUES (TIMESTAMP '2018-11-17 13:33:33')")
      .executeUpdate()
    conn.commit()

    conn.prepareStatement(
      "CREATE TABLE ch (c0 VARCHAR2(100 BYTE), c1 VARCHAR2(100 CHAR), c2 NCHAR(100)," +
        "c3 NVARCHAR2(100))").executeUpdate()
    // scalastyle:off nonascii
    val statement = conn.prepareStatement("INSERT INTO ch VALUES (?,?,?,?)")
    statement.setString(1, "上海")
    statement.setString(2, "杭州")
    statement.setString(3, "北京")
    statement.setString(4, "广州")
    statement.addBatch()
    statement.setString(1, "한국")
    statement.setString(2, "서울")
    statement.setString(3, "부산")
    statement.setString(4, "대구")
    statement.addBatch()
    statement.setString(1, "العربية")
    statement.setString(2, "القاهرة")
    statement.setString(3, "الجيزة")
    statement.setString(4, "الإسكندرية")
    statement.addBatch()
    statement.executeBatch()
    // insert a row with AL16UTF16 but not UTF8
    // scalastyle:on nonascii
    conn.commit()
  }

  test("SPARK-16625: Importing Oracle numeric types") {
    Seq("true", "false").foreach { flag =>
      withSQLConf((SQLConf.LEGACY_ALLOW_NEGATIVE_SCALE_OF_DECIMAL_ENABLED.key, flag)) {
        val df = sqlContext.read.jdbc(jdbcUrl, "numerics", new Properties)
        checkAnswer(df, Seq(Row(BigDecimal.valueOf(4), BigDecimal.valueOf(1.23),
          BigDecimal.valueOf(9999999999L), BigDecimal.valueOf(7456100))))
      }
    }
  }


  test("SPARK-12941: String datatypes to be mapped to VARCHAR(255) in Oracle") {
    // create a sample dataframe with string type
    val df1 = sparkContext.parallelize(Seq(("foo"))).toDF("x")
    // write the dataframe to the oracle table tbl
    df1.write.jdbc(jdbcUrl, "tbl2", new Properties)
    // read the table from the oracle
    val dfRead = sqlContext.read.jdbc(jdbcUrl, "tbl2", new Properties)
    // get the rows
    val rows = dfRead.collect()
    // verify the data type is inserted
    val types = rows(0).toSeq.map(x => x.getClass.toString)
    assert(types(0).equals("class java.lang.String"))
    // verify the value is the inserted correct or not
    assert(rows(0).getString(0).equals("foo"))
  }

  test("SPARK-16625: General data types to be mapped to Oracle") {
    val props = new Properties()
    props.put("oracle.jdbc.mapDateToTimestamp", "false")

    val schema = StructType(Seq(
      StructField("boolean_type", BooleanType, true),
      StructField("integer_type", IntegerType, true),
      StructField("long_type", LongType, true),
      StructField("float_Type", FloatType, true),
      StructField("double_type", DoubleType, true),
      StructField("byte_type", ByteType, true),
      StructField("short_type", ShortType, true),
      StructField("string_type", StringType, true),
      StructField("binary_type", BinaryType, true),
      StructField("date_type", DateType, true),
      StructField("timestamp_type", TimestampType, true)
    ))

    val tableName = "test_oracle_general_types"
    val booleanVal = true
    val integerVal = 1
    val longVal = 2L
    val floatVal = 3.0f
    val doubleVal = 4.0
    val byteVal = 2.toByte
    val shortVal = 5.toShort
    val stringVal = "string"
    val binaryVal = Array[Byte](6, 7, 8)
    val dateVal = Date.valueOf("2016-07-26")
    val timestampVal = Timestamp.valueOf("2016-07-26 11:49:45")

    val data = spark.sparkContext.parallelize(Seq(
      Row(
        booleanVal, integerVal, longVal, floatVal, doubleVal, byteVal, shortVal, stringVal,
        binaryVal, dateVal, timestampVal
      )))

    val dfWrite = spark.createDataFrame(data, schema)
    dfWrite.write.jdbc(jdbcUrl, tableName, props)

    val dfRead = spark.read.jdbc(jdbcUrl, tableName, props)
    val rows = dfRead.collect()
    // verify the data type is inserted
    val types = dfRead.schema.map(field => field.dataType)
    assert(types(0).equals(DecimalType(1, 0)))
    assert(types(1).equals(DecimalType(10, 0)))
    assert(types(2).equals(DecimalType(19, 0)))
    assert(types(3).equals(DecimalType(19, 4)))
    assert(types(4).equals(DecimalType(19, 4)))
    assert(types(5).equals(DecimalType(3, 0)))
    assert(types(6).equals(DecimalType(5, 0)))
    assert(types(7).equals(StringType))
    assert(types(8).equals(BinaryType))
    assert(types(9).equals(DateType))
    assert(types(10).equals(TimestampType))

    // verify the value is the inserted correct or not
    val values = rows(0)
    assert(values.getDecimal(0).compareTo(BigDecimal.valueOf(1)) == 0)
    assert(values.getDecimal(1).compareTo(BigDecimal.valueOf(integerVal)) == 0)
    assert(values.getDecimal(2).compareTo(BigDecimal.valueOf(longVal)) == 0)
    assert(values.getDecimal(3).compareTo(BigDecimal.valueOf(floatVal)) == 0)
    assert(values.getDecimal(4).compareTo(BigDecimal.valueOf(doubleVal)) == 0)
    assert(values.getDecimal(5).compareTo(BigDecimal.valueOf(byteVal)) == 0)
    assert(values.getDecimal(6).compareTo(BigDecimal.valueOf(shortVal)) == 0)
    assert(values.getString(7).equals(stringVal))
    assert(values.getAs[Array[Byte]](8).mkString.equals("678"))
    assert(values.getDate(9).equals(dateVal))
    assert(values.getTimestamp(10).equals(timestampVal))
  }

  test("SPARK-19318: connection property keys should be case-sensitive") {
    def checkRow(row: Row): Unit = {
      assert(row.getDecimal(0).equals(BigDecimal.valueOf(1)))
      assert(row.getDate(1).equals(Date.valueOf("1991-11-09")))
      assert(row.getTimestamp(2).equals(Timestamp.valueOf("1996-01-01 01:23:45")))
    }
    checkRow(sql("SELECT * FROM datetime where id = 1").head())
    sql("INSERT INTO TABLE datetime1 SELECT * FROM datetime where id = 1")
    checkRow(sql("SELECT * FROM datetime1 where id = 1").head())
  }

  test("SPARK-20557: column type TIMESTAMP with TIME ZONE should be recognized") {
    val dfRead = sqlContext.read.jdbc(jdbcUrl, "ts_with_timezone", new Properties)
    val rows = dfRead.collect()
    val types = rows(0).toSeq.map(x => x.getClass.toString)
    assert(types(1).equals("class java.sql.Timestamp"))
  }

  test("SPARK-47280: Remove timezone limitation for ORACLE TIMESTAMP WITH TIMEZONE") {
    val defaultJVMTimeZone = TimeZone.getDefault
    // Pick the timezone different from the current default time zone of JVM
    val sofiaTimeZone = TimeZone.getTimeZone("Europe/Sofia")
    val shanghaiTimeZone = TimeZone.getTimeZone("Asia/Shanghai")
    val localSessionTimeZone =
      if (defaultJVMTimeZone == shanghaiTimeZone) sofiaTimeZone else shanghaiTimeZone

    withSQLConf(SQLConf.SESSION_LOCAL_TIMEZONE.key -> localSessionTimeZone.getID) {
      checkAnswer(
        sqlContext.read.jdbc(jdbcUrl, "ts_with_timezone", new Properties),
        rsOfTsWithTimezone)
    }
  }

  test("Column TIMESTAMP with TIME ZONE(JVM timezone)") {
    withSQLConf(SQLConf.SESSION_LOCAL_TIMEZONE.key -> TimeZone.getDefault.getID) {
      val dfRead = sqlContext.read.jdbc(jdbcUrl, "ts_with_timezone", new Properties)
      Seq(PST, UTC).foreach(timeZone => {
        withDefaultTimeZone(timeZone) {
          checkAnswer(dfRead, rsOfTsWithTimezone)
        }
      })
    }
  }

  test("SPARK-18004: Make sure date or timestamp related predicate is pushed down correctly") {
    val props = new Properties()
    props.put("oracle.jdbc.mapDateToTimestamp", "false")

    val schema = StructType(Seq(
      StructField("date_type", DateType, true),
      StructField("timestamp_type", TimestampType, true)
    ))

    val tableName = "test_date_timestamp_pushdown"
    val dateVal = Date.valueOf("2017-06-22")
    val timestampVal = Timestamp.valueOf("2017-06-22 21:30:07")

    val data = spark.sparkContext.parallelize(Seq(
      Row(dateVal, timestampVal)
    ))

    val dfWrite = spark.createDataFrame(data, schema)
    dfWrite.write.jdbc(jdbcUrl, tableName, props)

    val dfRead = spark.read.jdbc(jdbcUrl, tableName, props)

    val millis = System.currentTimeMillis()
    val dt = new java.sql.Date(millis)
    val ts = new java.sql.Timestamp(millis)

    // Query Oracle table with date and timestamp predicates
    // which should be pushed down to Oracle.
    val df = dfRead.filter(dfRead.col("date_type").lt(dt))
      .filter(dfRead.col("timestamp_type").lt(ts))

    val parentPlan = df.queryExecution.executedPlan
    assert(parentPlan.isInstanceOf[WholeStageCodegenExec])
    val node = parentPlan.asInstanceOf[WholeStageCodegenExec]
    val metadata = node.child.asInstanceOf[RowDataSourceScanExec].metadata
    // The "PushedFilters" part should exist in Dataframe's
    // physical plan and the existence of right literals in
    // "PushedFilters" is used to prove that the predicates
    // pushing down have been effective.
    assert(metadata.get("PushedFilters").isDefined)
    assert(metadata("PushedFilters").contains(dt.toString))
    assert(metadata("PushedFilters").contains(ts.toString))

    val row = df.collect()(0)
    assert(row.getDate(0).equals(dateVal))
    assert(row.getTimestamp(1).equals(timestampVal))
  }

  test("SPARK-20427/SPARK-20921: read table use custom schema by jdbc api") {
    // default will throw IllegalArgumentException
    val e = intercept[org.apache.spark.SparkArithmeticException] {
      spark.read.jdbc(jdbcUrl, "tableWithCustomSchema", new Properties()).collect()
    }
    assert(e.getMessage.contains(
      "The 12312321321321312312312312123.0000000000 rounded half up from" +
        " 12312321321321312312312312123 cannot be represented as Decimal(38, 10)"))

    // custom schema can read data
    val props = new Properties()
    props.put("customSchema",
      s"ID DECIMAL(${DecimalType.MAX_PRECISION}, 0), N1 INT, N2 BOOLEAN")
    val dfRead = spark.read.jdbc(jdbcUrl, "tableWithCustomSchema", props)

    val rows = dfRead.collect()
    // verify the data type
    val types = rows(0).toSeq.map(x => x.getClass.toString)
    assert(types(0).equals("class java.math.BigDecimal"))
    assert(types(1).equals("class java.lang.Integer"))
    assert(types(2).equals("class java.lang.Boolean"))

    // verify the value
    val values = rows(0)
    assert(values.getDecimal(0).equals(new java.math.BigDecimal("12312321321321312312312312123")))
    assert(values.getInt(1).equals(1))
    assert(values.getBoolean(2) == false)
  }

  test("SPARK-22303: handle BINARY_DOUBLE and BINARY_FLOAT as DoubleType and FloatType") {
    val tableName = "oracle_types"
    val schema = StructType(Seq(
      StructField("d", DoubleType, true),
      StructField("f", FloatType, true)))
    val props = new Properties()

    // write it back to the table (append mode)
    val data = spark.sparkContext.parallelize(Seq(Row(1.1, 2.2f)))
    val dfWrite = spark.createDataFrame(data, schema)
    dfWrite.write.mode(SaveMode.Append).jdbc(jdbcUrl, tableName, props)

    // read records from oracle_types
    val dfRead = sqlContext.read.jdbc(jdbcUrl, tableName, new Properties)
    val rows = dfRead.collect()
    assert(rows.length == 1)

    // check data types
    val types = dfRead.schema.map(field => field.dataType)
    assert(types(0).equals(DoubleType))
    assert(types(1).equals(FloatType))

    // check values
    val values = rows(0)
    assert(values.getDouble(0) === 1.1)
    assert(values.getFloat(1) === 2.2f)
  }

  test("SPARK-22814 support date/timestamp types in partitionColumn") {
    val expectedResult = Set(
      (1, "2018-07-06", "2018-07-06 05:50:00"),
      (2, "2018-07-06", "2018-07-06 08:10:08"),
      (3, "2018-07-08", "2018-07-08 13:32:01"),
      (4, "2018-07-12", "2018-07-12 09:51:15")
    ).map { case (id, date, timestamp) =>
      Row(BigDecimal.valueOf(id), Date.valueOf(date), Timestamp.valueOf(timestamp))
    }

    // DateType partition column
    val df1 = spark.read.format("jdbc")
      .option("url", jdbcUrl)
      .option("dbtable", "datetimePartitionTest")
      .option("partitionColumn", "d")
      .option("lowerBound", "2018-07-06")
      .option("upperBound", "2018-07-20")
      .option("numPartitions", 3)
      // oracle.jdbc.mapDateToTimestamp defaults to true. If this flag is not disabled, column d
      // (Oracle DATE) will be resolved as Catalyst Timestamp, which will fail bound evaluation of
      // the partition column. E.g. 2018-07-06 cannot be evaluated as Timestamp, and the error
      // message says: Timestamp format must be yyyy-mm-dd hh:mm:ss[.fffffffff].
      .option("oracle.jdbc.mapDateToTimestamp", "false")
      .option("sessionInitStatement", "ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD'")
      .load()

    df1.logicalPlan match {
      case LogicalRelationWithTable(JDBCRelation(_, parts, _), _) =>
        val whereClauses = parts.map(_.asInstanceOf[JDBCPartition].whereClause).toSet
        assert(whereClauses === Set(
          """"D" < '2018-07-11' or "D" is null""",
          """"D" >= '2018-07-11' AND "D" < '2018-07-15'""",
          """"D" >= '2018-07-15'"""))
    }
    assert(df1.collect().toSet === expectedResult)

    // TimestampType partition column
    val df2 = spark.read.format("jdbc")
      .option("url", jdbcUrl)
      .option("dbtable", "datetimePartitionTest")
      .option("partitionColumn", "t")
      .option("lowerBound", "2018-07-04 03:30:00.0")
      .option("upperBound", "2018-07-27 14:11:05.0")
      .option("numPartitions", 2)
      .option("oracle.jdbc.mapDateToTimestamp", "false")
      .option("sessionInitStatement",
        "ALTER SESSION SET NLS_TIMESTAMP_FORMAT = 'YYYY-MM-DD HH24:MI:SS.FF'")
      .load()

    df2.logicalPlan match {
      case LogicalRelationWithTable(JDBCRelation(_, parts, _), _) =>
        val whereClauses = parts.map(_.asInstanceOf[JDBCPartition].whereClause).toSet
        assert(whereClauses === Set(
          """"T" < '2018-07-15 20:50:32.5' or "T" is null""",
          """"T" >= '2018-07-15 20:50:32.5'"""))
    }
    assert(df2.collect().toSet === expectedResult)
  }

  test("query JDBC option") {
    val expectedResult = Set(
      (1, "1991-11-09", "1996-01-01 01:23:45")
    ).map { case (id, date, timestamp) =>
      Row(BigDecimal.valueOf(id), Date.valueOf(date), Timestamp.valueOf(timestamp))
    }

    val query = "SELECT id, d, t FROM datetime WHERE id = 1"
    // query option to pass on the query string.
    val df = spark.read.format("jdbc")
      .option("url", jdbcUrl)
      .option("query", query)
      .option("oracle.jdbc.mapDateToTimestamp", "false")
      .load()
    assert(df.collect().toSet === expectedResult)

    // query option in the create table path.
    sql(
      s"""
         |CREATE OR REPLACE TEMPORARY VIEW queryOption
         |USING org.apache.spark.sql.jdbc
         |OPTIONS (url '$jdbcUrl',
         |   query '$query',
         |   oracle.jdbc.mapDateToTimestamp false)
       """.stripMargin.replaceAll("\n", " "))
    assert(sql("select id, d, t from queryOption").collect().toSet == expectedResult)
  }

  test("SPARK-32992: map Oracle's ROWID type to StringType") {
    val rows = spark.read.format("jdbc")
      .option("url", jdbcUrl)
      .option("query", "SELECT ROWID from datetime")
      .load()
      .collect()
    val types = rows(0).toSeq.map(x => x.getClass.toString)
    assert(types(0).equals("class java.lang.String"))
    assert(!rows(0).getString(0).isEmpty)
  }

  test("SPARK-44885: query row with ROWID type containing NULL value") {
    val rows = spark.read.format("jdbc")
      .option("url", jdbcUrl)
      // Rename column to `row_id` to prevent the following SQL error:
      //   ORA-01446: cannot select ROWID from view with DISTINCT, GROUP BY, etc.
      // See also https://stackoverflow.com/a/42632686/13300239
      .option("query", "SELECT rowid as row_id from datetime where d = {d '1991-11-09'}\n" +
        "union all\n" +
        "select null from dual")
      .load()
      .collect()
    assert(rows(0).getString(0).nonEmpty)
    assert(rows(1).getString(0) == null)
  }

  test("SPARK-42627: Support ORACLE TIMESTAMP WITH LOCAL TIME ZONE") {
    Seq("true", "false").foreach { flag =>
      withSQLConf((SQLConf.LEGACY_ORACLE_TIMESTAMP_MAPPING_ENABLED.key, flag)) {
        val df = spark.read.format("jdbc")
          .option("url", jdbcUrl)
          .option("dbtable", "test_ltz")
          .load()
        val row1 = df.collect().head.getTimestamp(0)
        assert(df.count() === 1)
        assert(row1 === Timestamp.valueOf("2018-11-17 13:33:33"))

        df.write.format("jdbc")
          .option("url", jdbcUrl)
          .option("dbtable", "test_ltz" + flag)
          .save()

        val df2 = spark.read.format("jdbc")
          .option("url", jdbcUrl)
          .option("dbtable", "test_ltz" + flag)
          .load()
        checkAnswer(df2, Row(row1))
      }
    }
  }

  test("SPARK-47761: Reading ANSI INTERVAL Types") {
    val df: String => DataFrame = query => spark.read.format("jdbc")
      .option("url", jdbcUrl)
      .option("query", query)
      .load()
    checkAnswer(df("SELECT INTERVAL '1-2' YEAR(1) TO MONTH as i0 FROM dual"),
      Row(Period.of(1, 2, 0)))
    checkAnswer(df("SELECT INTERVAL '1-2' YEAR(2) TO MONTH as i1 FROM dual"),
      Row(Period.of(1, 2, 0)))
    checkAnswer(df("SELECT INTERVAL '12345-2' YEAR(9) TO MONTH as i2 FROM dual"),
      Row(Period.of(12345, 2, 0)))
    checkAnswer(df("SELECT INTERVAL '1 12:23:56' DAY(1) TO SECOND(0) as i3 FROM dual"),
      Row(Duration.ofDays(1).plusHours(12).plusMinutes(23).plusSeconds(56)))
    checkAnswer(df("SELECT INTERVAL '1 12:23:56.12' DAY TO SECOND(2) as i4 FROM dual"),
      Row(Duration.ofDays(1).plusHours(12).plusMinutes(23).plusSeconds(56).plusMillis(120)))
    checkAnswer(df("SELECT INTERVAL '1 12:23:56.1234' DAY TO SECOND(4) as i5 FROM dual"),
      Row(Duration.ofDays(1).plusHours(12).plusMinutes(23).plusSeconds(56).plusMillis(123)
        .plusNanos(400000)))
    checkAnswer(df("SELECT INTERVAL '1 12:23:56.123456' DAY TO SECOND(6) as i6 FROM dual"),
      Row(Duration.ofDays(1).plusHours(12).plusMinutes(23).plusSeconds(56).plusMillis(123)
        .plusNanos(456000)))
    checkAnswer(df("SELECT INTERVAL '1 12:23:56.12345678' DAY TO SECOND(8) as i7 FROM dual"),
      Row(Duration.ofDays(1).plusHours(12).plusMinutes(23).plusSeconds(56).plusMillis(123)
        .plusNanos(456000)))
  }

  test("SPARK-47856: NCHAR and NVARCHAR") {
    val df = spark.read.jdbc(jdbcUrl, "ch", new Properties)
    // scalastyle:off nonascii
    checkAnswer(df, Seq(
      Row("上海", "杭州", "北京".padTo(100, ' '), "广州"),
      Row("한국", "서울", "부산".padTo(100, ' '), "대구"),
      Row("العربية", "القاهرة", "الجيزة".padTo(100, ' '), "الإسكندرية")
    ))
    // scalastyle:on nonascii
    val schema = df.schema
    Seq(0, 1).foreach { i =>
      assert(schema(i).dataType === StringType)
      assert(schema(i).metadata.getString(CharVarcharUtils.CHAR_VARCHAR_TYPE_STRING_METADATA_KEY)
        === VarcharType(100).catalogString)
    }
    Seq(2, 3).foreach { i =>
      assert(schema(i).dataType === StringType)
      assert(!schema(i).metadata.contains(CharVarcharUtils.CHAR_VARCHAR_TYPE_STRING_METADATA_KEY))
    }
  }
}
