rdblue commented on a change in pull request #1870: URL: https://github.com/apache/iceberg/pull/1870#discussion_r547565476
########## File path: core/src/main/java/org/apache/iceberg/jdbc/JdbcTable.java ########## @@ -0,0 +1,187 @@ +/* + * 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.iceberg.jdbc; + +import com.fasterxml.jackson.core.JsonProcessingException; +import java.sql.Connection; +import java.sql.PreparedStatement; +import java.sql.ResultSet; +import java.sql.SQLException; +import java.util.List; +import java.util.Map; +import org.apache.iceberg.catalog.Namespace; +import org.apache.iceberg.catalog.TableIdentifier; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.relocated.com.google.common.collect.Maps; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class JdbcTable { + public static final String SQL_TABLE_NAME = "iceberg_tables"; + public static final String SQL_TABLE_DDL = + "CREATE TABLE " + JdbcTable.SQL_TABLE_NAME + + "(catalog_name VARCHAR(1255) NOT NULL," + + "table_namespace VARCHAR(1255) NOT NULL," + + "table_name VARCHAR(1255) NOT NULL," + + "metadata_location VARCHAR(32768)," + + "previous_metadata_location VARCHAR(32768)," + + "PRIMARY KEY (catalog_name, table_namespace, table_name)" + + ")"; + public static final String SQL_SELECT = "SELECT * FROM " + SQL_TABLE_NAME + + " WHERE catalog_name = ? AND table_namespace = ? AND table_name = ? "; + public static final String SQL_SELECT_ALL = "SELECT * FROM " + SQL_TABLE_NAME + + " WHERE catalog_name = ? AND table_namespace = ?"; + public static final String SQL_UPDATE_METADATA_LOCATION = "UPDATE " + SQL_TABLE_NAME + + " SET metadata_location = ? , previous_metadata_location = ? " + + " WHERE catalog_name = ? AND table_namespace = ? AND table_name = ? AND metadata_location = ?"; + public static final String SQL_INSERT = "INSERT INTO " + SQL_TABLE_NAME + + " (catalog_name, table_namespace, table_name, metadata_location, previous_metadata_location) " + + " VALUES (?,?,?,?,?)"; + public static final String SQL_UPDATE_TABLE_NAME = "UPDATE " + SQL_TABLE_NAME + + " SET table_namespace = ? , table_name = ? " + + " WHERE catalog_name = ? AND table_namespace = ? AND table_name = ? "; + public static final String SQL_DELETE = "DELETE FROM " + SQL_TABLE_NAME + + " WHERE catalog_name = ? AND table_namespace = ? AND table_name = ? "; + + private static final Logger LOG = LoggerFactory.getLogger(JdbcTable.class); + private final String catalogName; + private final Connection dbConn; + + public JdbcTable(Connection dbConn, String catalogName) { + this.dbConn = dbConn; + this.catalogName = catalogName; + } + + public void setAutoCommitOff() throws SQLException { + this.dbConn.setAutoCommit(false); + } + + public void setAutoCommitOn() throws SQLException { + this.dbConn.setAutoCommit(true); + } + + public void commit() throws SQLException { + this.dbConn.commit(); + } + + public void rollback() throws SQLException { + this.dbConn.rollback(); + } + + public boolean isExists(TableIdentifier tableIdentifier) { + try { + return !this.get(tableIdentifier).isEmpty(); + } catch (SQLException | JsonProcessingException throwables) { + return false; + } + } + + public Map<String, String> get(TableIdentifier tableIdentifier) throws SQLException, JsonProcessingException { + Map<String, String> table = Maps.newHashMap(); + PreparedStatement sql = dbConn.prepareStatement(SQL_SELECT); + sql.setString(1, catalogName); + sql.setString(2, JdbcUtil.namespaceToString(tableIdentifier.namespace())); Review comment: Rather than using JSON to encode the namespace, I suggest converting it to a String using `Joiner.on(".")`. There's a trade-off to simplifying the problem by doing it that way: both ```a.`b.c` ``` and `a.b.c` end up as `a.b.c`. That has two effects: 1. Namespaces that "collide" like that are considered the same namespace 2. When listing namespace `a` the result is `[b]` and not `[b.c, b]` I think that those are fine. For the collisions, I think it is rare for users to _want_ namespaces that can collide but are not the same. If someone creates the table ```a.`b.c`.table_name``` then I really doubt that everyone wants to escape `b.c` every time they type the identifier. Everyone is going to type `a.b.c.table_name` anyway, which would return incorrect results if both tables exist. So not allowing namespaces that conflict is actually a good thing. This is exactly what Iceberg does to look up columns in a table, too. All column names are converted to a lookup key by joining the parts with `.`. Columns that have different structures but identical names aren't allowed, and I think it is better that way. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
