xuefuz commented on a change in pull request #8007: [FLINK-11474][table] Add ReadableCatalog, ReadableWritableCatalog, and other … URL: https://github.com/apache/flink/pull/8007#discussion_r269800930
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/api/catalog/ReadableCatalog.java ########## @@ -0,0 +1,126 @@ +/* + * 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.api.catalog; + +import org.apache.flink.table.api.catalog.exceptions.DatabaseNotExistException; +import org.apache.flink.table.api.catalog.exceptions.TableNotExistException; +import org.apache.flink.table.plan.stats.TableStats; + +import java.util.List; + +/** + * This interface is responsible for reading database/table/views/UDFs from a registered catalog. + * It connects a registered catalog and Flink's Table API. + */ +public interface ReadableCatalog { + + /** + * Open the catalog. Used for any required preparation in initialization phase. + */ + void open(); + + /** + * Close the catalog when it is no longer needed and release any resource that it might be holding. + */ + void close(); + + /** + * Get the default database of this type of catalog. This is used when users refers an object in the catalog + * without specifying a database. For example, the default db in a Hive Metastore is 'default' by default. + * + * @return the name of the default database + */ + String getDefaultDatabaseName(); + + /** + * Set the default database. A default database is used when users refers an object in the catalog + * without specifying a database. + * + * @param databaseName the name of the database + */ + void setDefaultDatabaseName(String databaseName); + + // ------ databases ------ + /** + * Get the names of all databases in this catalog. + * + * @return The list of the names of all databases + */ + List<String> listDatabases(); + + /** + * Get a database from this catalog. + * + * @param dbName Name of the database + * @return The requested database + * @throws DatabaseNotExistException if the database does not exist + */ + CatalogDatabase getDatabase(String dbName) throws DatabaseNotExistException; + + /** + * Check if a database exists in this catalog. + * + * @param dbName Name of the database + */ + boolean databaseExists(String dbName); + + /** + * Gets paths of all tables and views under this database. An empty list is returned if none exists. + * + * @return A list of the names of all tables and views in this database + * @throws DatabaseNotExistException if the database does not exist + */ + List<String> listTables(String dbName) throws DatabaseNotExistException; Review comment: Maybe you didn't have all the context, but this has been discussed previously and what we have now is what we concluded. ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services
