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org.apache.spark.sql.jdbc.DB2Dialect.scala Maven / Gradle / Ivy

/*
 * 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.sql.Types
import java.util.Locale

import org.apache.spark.sql.types._

private object DB2Dialect extends JdbcDialect {

  override def canHandle(url: String): Boolean =
    url.toLowerCase(Locale.ROOT).startsWith("jdbc:db2")

  override def getCatalystType(
      sqlType: Int,
      typeName: String,
      size: Int,
      md: MetadataBuilder): Option[DataType] = sqlType match {
    case Types.REAL => Option(FloatType)
    case Types.OTHER =>
      typeName match {
        case "DECFLOAT" => Option(DecimalType(38, 18))
        case "XML" => Option(StringType)
        case t if (t.startsWith("TIMESTAMP")) => Option(TimestampType) // TIMESTAMP WITH TIMEZONE
        case _ => None
      }
    case _ => None
  }

  override def getJDBCType(dt: DataType): Option[JdbcType] = dt match {
    case StringType => Option(JdbcType("CLOB", java.sql.Types.CLOB))
    case BooleanType => Option(JdbcType("CHAR(1)", java.sql.Types.CHAR))
    case ShortType | ByteType => Some(JdbcType("SMALLINT", java.sql.Types.SMALLINT))
    case _ => None
  }

  override def isCascadingTruncateTable(): Option[Boolean] = Some(false)

  // scalastyle:off line.size.limit
  // See https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0000980.html
  // scalastyle:on line.size.limit
  override def renameTable(oldTable: String, newTable: String): String = {
    s"RENAME TABLE $oldTable TO $newTable"
  }

  // scalastyle:off line.size.limit
  // See https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0000888.html
  // scalastyle:on line.size.limit
  override def getUpdateColumnTypeQuery(
      tableName: String,
      columnName: String,
      newDataType: String): String =
    s"ALTER TABLE $tableName ALTER COLUMN ${quoteIdentifier(columnName)}" +
      s" SET DATA TYPE $newDataType"

  // scalastyle:off line.size.limit
  // See https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.5.0/com.ibm.db2.luw.sql.ref.doc/doc/r0000888.html
  // scalastyle:on line.size.limit
  override def getUpdateColumnNullabilityQuery(
      tableName: String,
      columnName: String,
      isNullable: Boolean): String = {
    val nullable = if (isNullable) "DROP NOT NULL" else "SET NOT NULL"
    s"ALTER TABLE $tableName ALTER COLUMN ${quoteIdentifier(columnName)} $nullable"
  }
}




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