/**
* The CREATE TABLE AS SELECT(CTAS) syntax requires CREATE/DROP TABLE operations via Catalog on the JM side,
* so this interface should extends Serializable interface, then it can be serialized as a part of {@link JobGraph}.
*/
@PublicEvolving
public interface Catalog extends Serializable {
/**
* This method is used to infer the default options for {@link CatalogBaseTable} through {@link Catalog} options to compile
* the sql successfully by planner when using the {@code Create Table As Select} syntax.
*
* Assuming an user want to select data from a kafka table and then insert the result to mysql table, if the mysql table is not existed in
* in physical mysql storage, user also doesn't want to create the table manually in mysql side because of complex type mapping.
* User can create the {@link JdbcCatalog} firstly which connect to the msyql instance, then use
* {@code CREATE TABLE `mysql`.`user_db`.`order_cnt` AS SELECT * FROM `KafkaTable`} syntax, it is convenient to load data from kafka
* to msyql. Due to the {@link JdbcCatalog} has provides user, password, url and other options, so user doesn't need to fill the
* option in the query. If user doesn't specify the target table required options, planner will call this method to fill the options to
* {@link CatalogBaseTable} which are need to compile sql by planner.
*
* <p>{@link JdbcCatalog} example:
* <pre>{@code
* // If the user does not set any Table's options,
* // then the implementation of JdbcCatalog#inferTableOptions
* // can be like this to avoid the execution failure.
* public CatalogBaseTable inferTableOptions(ObjectPath tablePath, CatalogTable table) {
* Map<String, String> tableOptions = table.getOptions();
* tableOptions.put("connector", "jdbc");
* tableOptions.put("url", getBaseUrl());
* tableOptions.put("table-name", tablePath.getObjectName());
* tableOptions.put("username", getUsername());
* tableOptions.put("password", getPassword());
* return table.copy(tableOptions);
* }
* }</pre>
*/
default CatalogBaseTable inferTableOptions(ObjectPath tablePath, CatalogTable table) {
throw new UnsupportedOperationException();
}
}
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