convert DateType to TimeStampType because a df from parquet cannot publish DateTypes to a hive table (see issue 6384)

scala-spark-datetype-to-timestamptype

import org.apache.spark.sql.types.{DateType, TimestampType}
import org.apache.spark.sql.DataFrame
  /**
    * convert DateType to TimeStampType because a df from parquet cannot publish DateTypes to a hive table
    * https://stackoverflow.com/questions/37357009/cloudera-5-6-parquet-does-not-support-date-see-hive-6384
    * @param df spark dataframe
    * @return spark dataframe
    */
  def convertDateToTimestamp(df: DataFrame): DataFrame ={
    val convertedDf = df.columns.foldLeft(df){(memoDf, colName) =>
      if (memoDf.schema(colName).dataType == DateType) {memoDf.withColumn(colName, memoDf(colName).cast(TimestampType))}
      else memoDf
    }
    convertedDf
  }