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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.flink.table.util
import org.apache.flink.table.api.{TableEnvironment, TableException}
import org.apache.flink.types.Row
import java.util
import scala.collection.mutable
import scala.collection.JavaConversions._
/**
* Utility to describe table or describe column.
*
*/
object DescribeTableColumn extends Logging {
/**
* Describes info of a table, including table schema and table statistics.
*
* @param tableEnv The [[TableEnvironment]] in which the given table name is registered.
* @param tablePath The table path under which the table is registered in [[TableEnvironment]].
* tablePath can be a single name(e.g. Array("MyTable")) associated with a table
* registered as Table, or can be a nest names
* (e.g. Array("MyCatalog", "MyDb", "MyTable")) associated with a table
* registered as member of a [[org.apache.flink.table.catalog.ReadableCatalog]].
* @param isRich Whether need more information except for basic table info or not.
* @return tableSchema if isRich is false, else return more info such as
* table statistics.
*/
def describeTable(
tableEnv: TableEnvironment,
tablePath: Array[String],
isRich: Boolean): util.List[Row] = {
val tableName = tablePath.mkString(".")
val tableOpt = tableEnv.getTable(tablePath)
if (tableOpt.isEmpty) {
throw new TableException(s"Table '$tableName' was not found.")
}
val table = tableOpt.get
val data = new mutable.ArrayBuffer[Row]
val rowType = table.getRowType(tableEnv.getTypeFactory)
rowType.getFieldList.foreach { f =>
data += Row.of(f.getName, f.getType.getSqlTypeName.name,
if (f.getType.isNullable) "YES" else "NO")
}
if (isRich) {
data += Row.of("", "", "")
data += Row.of("# Detailed Table Information", "", "")
data += Row.of("table_name", tableName, "")
val tableStats = Option(tableEnv.getTableStats(tablePath))
data += Row.of("row_count",
tableStats.flatMap(ts => Option(ts.rowCount).map(_.toString)).getOrElse("NULL"), "")
}
data.toList
}
/**
* Describes info of a column, including name, type, isNullable and column statistics.
*
* @param tableEnv The [[TableEnvironment]] in which the given table name is registered.
* @param tablePath The table path under which the table is registered in [[TableEnvironment]].
* tablePath can be a single name(e.g. Array("MyTable")) associated with a table
* registered as Table, or can be a nest names
* (e.g. Array("MyCatalog", "MyDb", "MyTable")) associated with a table
* registered as member of a [[org.apache.flink.table.catalog.ReadableCatalog]].
* @param column The column to describe.
* @param isRich Whether need more information except for column or not.
* @return column basic info if isRich is false, else return more info such as column statistics.
*/
def describeColumn(
tableEnv: TableEnvironment,
tablePath: Array[String],
column: String,
isRich: Boolean): util.List[Row] = {
val tableName = tablePath.mkString(".")
val tableOpt = tableEnv.getTable(tablePath)
if (tableOpt.isEmpty) {
throw new TableException(s"Table '$tableName' was not found.")
}
val table = tableOpt.get
val data = new mutable.ArrayBuffer[Row]
val field = table.getRowType(tableEnv.getTypeFactory).getFieldList
.find(_.getName.equalsIgnoreCase(column))
field match {
case Some(f) =>
data += Row.of("column_name", f.getName)
data += Row.of("column_type", f.getType.getSqlTypeName.name())
data += Row.of("is_nullable", if (f.getType.isNullable) "YES" else "NO")
case _ => throw new TableException(s"Column $column was not found.")
}
if (isRich) {
val columnStats = Option(tableEnv.getTableStats(tablePath))
.flatMap(ts => Option(ts.colStats.get(column)))
data += Row.of("ndv",
columnStats.flatMap(cs => Option(cs.ndv).map(_.toString)).getOrElse("NULL"))
data += Row.of("null_count",
columnStats.flatMap(cs => Option(cs.nullCount).map(_.toString)).getOrElse("NULL"))
data += Row.of("avg_len",
columnStats.flatMap(cs => Option(cs.avgLen).map(_.toString)).getOrElse("NULL"))
data += Row.of("max_len",
columnStats.flatMap(cs => Option(cs.maxLen).map(_.toString)).getOrElse("NULL"))
data += Row.of("max",
columnStats.flatMap(cs => Option(cs.max).map(_.toString)).getOrElse("NULL"))
data += Row.of("min",
columnStats.flatMap(cs => Option(cs.min).map(_.toString)).getOrElse("NULL"))
}
data.toList
}
}
