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Current state: ["Under Discussion"]
Discussion thread: here httpshttp://mail-archives.apache.org/mod_mbox/flink-dev/201909.mbox/%3CFFD7AA16-D05F-4CFD-A908-8DDE28FB561C%40gmail.com%3Eapache-flink-mailing-list-archive.1008284.n3.nabble.com/DISCUSS-FLIP-69-Flink-SQL-DDL-Enhancement-td33090.html
JIRA: here: TBD
Released: TBD
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
Motivation
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In flink 1.9, we have introduced some awesome features such as complete catalog support[1] and sql ddl support[2]. These features have been a critical integration for Flink to be able to manage data and metadata like a classic RDBMS and make developers more easy to construct their real-time/off-line warehouse or sth similar base on flink.
Despite that big advancement, there is still a lack of support on how Flink SQL DDL to manage metadata and data.
- Don’t support show/describe/use catalog(s)
- Don’t support create/drop/alter/use/show/desc database(s)
- Don’t support show/desc table(s) and create table as select
- Don’t support create/drop/show function(s)
- Don’t support create/drop/show/desc view(s)
Goals:
We would like to achieve the following goals in this FLIP.
- Add Catalog DDL enhancement support
- Add Database DDL enhancement support
- Add Table DDL enhancement support
- Add Function DDL enhancement support
Note:
The following issues are out of the scope of this FLIP. They will be taken care of by other teams/committers.
- DDL related to View(s)
- DDL related to Partition(s)
- Make SQL CLIENT and tEnv.sqlUpdate support new added ddl in a unified way
Public Interfaces
Briefly list any new interfaces that will be introduced as part of this proposal or any existing interfaces that will be removed or changed. The purpose of this section is to concisely call out the public contract that will come along with this feature.
Proposed Changes
There are a few DDLs following that are already supported in SQL client. We want them should be migrated using the parser approach.
A public interface is any change to the following:
Binary log formatThe network protocol and api behaviorAny class in the public packages under clientsConfiguration, especially client configurationorg/apache/kafka/common/serializationorg/apache/kafka/commonorg/apache/kafka/common/errorsorg/apache/kafka/clients/producerorg/apache/kafka/clients/consumer (eventually, once stable)
MonitoringCommand line tools and argumentsAnything else that will likely break existing users in some way when they upgrade
Proposed Changes
Catalog DDL:
We propose to add the following DDLs related to catalog operations.
showCatalogsStatement
SHOW CATALOGS
Return all databases in the current catalog.
note: already support in sql client but need support in tEnv.sqlQuery();
describeCatalogStatement
DESCRIBE CATALOG [ EXTENDED] catalogName
Return the metadata of an existing catalogName
EXTENDED:
Display the catalog properties.
useCatalogStatement
USE CATALOG catalogName
Set the current catalog.
note: already support in sql client but need support in tEnv.sqlQuery();
Database DDL:
We propose to add the following DDLs related to database operations.
createDatabaseStatement:
CREATE DATABASE [ IF NOT EXISTS ] [ catalogName.] dataBaseName
[ COMMENT database_comment ]
[WITH ( name=value [, name=value]*)]
IF NOT EXISTS:
If a database with the same name already exists, nothing will happen.
dropDatabaseStatement:
DROP DATABASE [ IF EXISTS ] [ catalogName.] dataBaseName
[ (RESTRICT|CASCADE)]
IF EXISTS
If the database to drop does not exist, nothing happens.
RESTRICT
Dropping a non-empty database triggers an exception. Enabled by default.
CASCADE
Dropping a non-empty database also drops all associated tables and functions.
alterDatabaseStatement:
ALTER DATABASE [ catalogName.] dataBaseName SET DBPROPERTIES
( name=value [, name=value]*)
Set one or more properties in the specified database. If a particular property is already set in the database, override the old value with the new one.
useDatabaseStatement:
USE [ catalogName.] dataBaseName
Set the current database. All subsequent commands that do not explicitly specify a database will use this one. If the provided database does not exist, an exception is thrown.
note: already support in sql client but need support in tEnv.sqlQuery();
showDatabasesStatement:
SHOW DATABASES
Return all databases in the current catalog.
note: already support in sql client but need support in tEnv.sqlQuery();
descDatabaseStatement:
DESCRIBE DATABASE [ EXTENDED] [ catalogName.] dataBasesName
Return the metadata of an existing database (name, comment).
EXTENDED:
Display the database properties.
Table DDL:
We propose to add the following DDLs related to table operations.
showTablesStatement:
SHOW TABLES
Return all tables in the current database.
note: already support in sql client but need support in tEnv.sqlQuery();
descTableStatement:
DESCRIBE [ EXTENDED] [[catalogName.] dataBasesName].tableName
Return the metadata of an existing table (column names, data types, and comments).
EXTENDED
Display detailed information about the table, including table type, properties and so on.
note: already support in sql client but need support in tEnv.sqlQuery();
alterTableStatement:
ALTER TABLE [[catalogName.] dataBasesName].tableName
REAME TO newTableName
Rename an existing table.
ALTER TABLE [[catalogName.] dataBasesName].tableName
SET TBLROPERTIES ( name=value [, name=value]*)
Set the properties of an existing table
Function DDL:
createFunctionStatement:
CREATE FUNCTION
[IF NOT EXISTS] [[catalogName.]databaseName.]functionName AS className.
Create a function indicated by a className
IF NOT EXISTS
If a function with the same name already exists, nothing will happen.
dropFunctionStatement:
DROP FUNCTION [IF EXISTS]
[[catalogName.]databaseName.]functionName.
Create a function indicated by a className
IF EXISTS
If a function with the same name not exists, nothing will happen.
alterFunctionStatement:
ALTER FUNCTION [IF EXISTS] [[catalogName.]databaseName.]functionName
RENAME TO new_name;
Rename a non-temporary function to new name.
IF EXISTS
If a function with the same name not exists, nothing will happen.
showFunctionsStatement:
SHOW FUNCTIONS
Return all functions in the current database.
note: already support in sql client but need support in tEnv.sqlQuery();Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.
Compatibility, Deprecation, and Migration Plan
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