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

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/*
 * 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 org.apache.spark.sql.types._


private case object TeradataDialect extends JdbcDialect {

  override def canHandle(url: String): Boolean = { url.startsWith("jdbc:teradata") }

  override def getJDBCType(dt: DataType): Option[JdbcType] = dt match {
    case StringType => Some(JdbcType("VARCHAR(255)", java.sql.Types.VARCHAR))
    case BooleanType => Option(JdbcType("CHAR(1)", java.sql.Types.CHAR))
    case _ => None
  }

  // Teradata does not support cascading a truncation
  override def isCascadingTruncateTable(): Option[Boolean] = Some(false)

  /**
   * The SQL query used to truncate a table. Teradata does not support the 'TRUNCATE' syntax that
   * other dialects use. Instead, we need to use a 'DELETE FROM' statement.
   * @param table The table to truncate.
   * @param cascade Whether or not to cascade the truncation. Default value is the
   *                value of isCascadingTruncateTable(). Teradata does not support cascading a
   *                'DELETE FROM' statement (and as mentioned, does not support 'TRUNCATE' syntax)
   * @return The SQL query to use for truncating a table
   */
  override def getTruncateQuery(
      table: String,
      cascade: Option[Boolean] = isCascadingTruncateTable): String = {
    s"DELETE FROM $table ALL"
  }
}