org.apache.spark.sql.catalyst.sqlgenerator.BasicSQLDialect.scala Maven / Gradle / Ivy

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A library for optimizing/rewriting/auditing SQL and easy to plugin new strategies

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package org.apache.spark.sql.catalyst.sqlgenerator

import java.sql.Connection

import org.apache.spark.sql.catalyst.dsl.plans._
import org.apache.spark.sql.execution.LogicalRDD
import org.apache.spark.sql.execution.datasources.LogicalRelation
import tech.mlsql.sqlbooster.meta.ViewCatalyst

/**
  * 2019-07-14 WilliamZhu([email protected])
  */
class BasicSQLDialect extends SQLDialect {
  override def canHandle(url: String): Boolean = url.toLowerCase().startsWith("jdbc:mysql")

  override def quote(name: String): String = {
    "`" + name.replace("`", "``") + "`"
  }

  override def explainSQL(sql: String): String = s"EXPLAIN $sql"

  override def relation(relation: LogicalRelation): String = {
    val view = relation.select(relation.output: _*)
    ViewCatalyst.meta.getViewNameByLogicalPlan(view) match {
      case Some(i) => i
      case None => ViewCatalyst.meta.getTableNameByLogicalPlan(relation.logicalPlan) match {
        case Some(i) => i
        case None => null
      }
    }


  }

  override def relation2(relation: LogicalRDD): String = {
    ViewCatalyst.meta.getTableNameByLogicalPlan(relation.logicalPlan) match {
      case Some(i) => i
      case None => null
    }
  }

  override def maybeQuote(name: String): String = {
    name
  }

  override def getIndexes(conn: Connection, url: String, tableName: String): Set[String] = {
    Set()
  }

  override def getTableStat(conn: Connection, url: String, tableName: String): (Option[BigInt], Option[Long]) = {
    (None, None)
  }

  override def enableCanonicalize: Boolean = false


}