[GitHub] [spark] cloud-fan commented on a change in pull request #29168: [SPARK-32375][SQL] Basic functionality of table catalog v2 for JDBC

[GitBox <gi...@apache.org>]

cloud-fan commented on a change in pull request #29168:
URL: https://github.com/apache/spark/pull/29168#discussion_r459927768



##########
File path: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/jdbc/JDBCTableCatalog.scala
##########
@@ -0,0 +1,161 @@
+/*
+ * 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.execution.datasources.v2.jdbc
+
+import java.sql.{Connection, SQLException}
+
+import scala.collection.JavaConverters._
+
+import org.apache.spark.internal.Logging
+import org.apache.spark.sql.catalyst.analysis.{NoSuchNamespaceException, NoSuchTableException}
+import org.apache.spark.sql.connector.catalog.{Identifier, Table, TableCatalog, TableChange}
+import org.apache.spark.sql.connector.expressions.Transform
+import org.apache.spark.sql.execution.datasources.jdbc.{JDBCOptions, JdbcOptionsInWrite, JDBCRDD, JdbcUtils}
+import org.apache.spark.sql.internal.SQLConf
+import org.apache.spark.sql.jdbc.{JdbcDialect, JdbcDialects}
+import org.apache.spark.sql.types.StructType
+import org.apache.spark.sql.util.CaseInsensitiveStringMap
+
+class JDBCTableCatalog extends TableCatalog with Logging {
+
+  private var catalogName: String = null
+  private var options: JDBCOptions = _
+  private var dialect: JdbcDialect = _
+
+  override def name(): String = {
+    require(catalogName != null, "The JDBC table catalog is not initialed")
+    catalogName
+  }
+
+  override def initialize(name: String, options: CaseInsensitiveStringMap): Unit = {
+    assert(catalogName == null, "The JDBC table catalog is already initialed")
+    catalogName = name
+
+    val map = options.asCaseSensitiveMap().asScala.toMap
+    // The `JDBCOptions` checks the existence of the table option. This is required by JDBC v1, but
+    // JDBC V2 only knows the table option when loading a table. Here we put a table option with a
+    // fake value, so that it can pass the check of `JDBCOptions`.
+    this.options = new JDBCOptions(map + (JDBCOptions.JDBC_TABLE_NAME -> "__invalid_dbtable"))
+    dialect = JdbcDialects.get(this.options.url)
+  }
+
+  override def listTables(namespace: Array[String]): Array[Identifier] = {
+    checkNamespace(namespace)
+    withConnection { conn =>
+      val rs = conn.getMetaData
+        .getTables(null, schemaPattern(namespace), "%", Array("TABLE"));
+      new Iterator[Identifier] {
+        def hasNext = rs.next()
+        def next = Identifier.of(namespace, rs.getString("TABLE_NAME"))
+      }.toArray
+    }
+  }
+
+  override def tableExists(ident: Identifier): Boolean = {
+    checkNamespace(ident.namespace())
+    val writeOptions = new JdbcOptionsInWrite(
+      options.parameters + (JDBCOptions.JDBC_TABLE_NAME -> getTableName(ident)))
+    withConnection(JdbcUtils.tableExists(_, writeOptions))
+  }
+
+  override def dropTable(ident: Identifier): Boolean = {
+    checkNamespace(ident.namespace())
+    withConnection { conn =>
+      try {
+        JdbcUtils.dropTable(conn, getTableName(ident), options)
+        true
+      } catch {
+        case _: SQLException => false
+      }
+    }
+  }
+
+  override def renameTable(oldIdent: Identifier, newIdent: Identifier): Unit = {
+    checkNamespace(oldIdent.namespace())
+    withConnection { conn =>
+      JdbcUtils.renameTable(conn, getTableName(oldIdent), getTableName(newIdent), options)
+    }
+  }
+
+  override def loadTable(ident: Identifier): Table = {
+    checkNamespace(ident.namespace())
+    val optionsWithTableName = new JDBCOptions(
+      options.parameters + (JDBCOptions.JDBC_TABLE_NAME -> getTableName(ident)))
+    try {
+      val schema = JDBCRDD.resolveTable(optionsWithTableName)
+      JDBCTable(ident, schema, optionsWithTableName)
+    } catch {
+      case _: SQLException => throw new NoSuchTableException(ident)
+    }
+  }
+
+  override def createTable(
+      ident: Identifier,
+      schema: StructType,
+      partitions: Array[Transform],
+      properties: java.util.Map[String, String]): Table = {
+      checkNamespace(ident.namespace())

Review comment:
       nit: wrong indentation.




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