[Feature request] `ALTER REL TABLE GROUP`: Add `FROM ... TO ...` statement (hashtag2922)

[vikramsubramanian]

It would be nice, if we could add additional node table pairs via FROM ... TO after creation of a REL TABLE GROUP relationship table. For example you need to alter database schema in the course of app progress. Or imagine an app, that allows structured, user-generated content via some kind of plugin system. This requires users to create additional tables. These tables might need to have relations to other tables. Some of these relations might have been instantiated via REL TABLE GROUP. Vice versa, same goes for DROP. Currently there is no ALTER in combination with manipulation of FROM ... TO afterwards. At least I couldn't find it in below resources:

)

[mayil-ai[bot]]

We're not sure how to solve this one.

but here are some ideas that might help you get started -

Summary: Feature request to add the ability to alter REL TABLE GROUP with FROM ... TO ... statement for adding additional node table pairs after the creation of the relationship table.

Possible Solution

To implement the feature request for ALTER REL TABLE GROUP with FROM ... TO ... statement to alter database schema, follow these steps:

• Extend the parser to recognize the new ALTER REL TABLE GROUP syntax with FROM ... TO ... clauses.

  • Modify the ANTLR grammar to include the new syntax for ALTER REL TABLE GROUP.
  • Update CypherParser::kU_AlterTableContext and related parsing functions to handle the new syntax.

• Update the Transformer class to transform the new ALTER REL TABLE GROUP syntax into an internal representation.

  • Add new methods in Transformer to handle the transformation of the new ALTER REL TABLE GROUP syntax.
  • These methods should create AlterRelTableGroupAdd and AlterRelTableGroupDrop statements or similar, depending on the operation.

• Implement the execution logic for the new ALTER REL TABLE GROUP operations.

  • Create new classes, such as AlterRelTableGroupAdd and AlterRelTableGroupDrop, that inherit from a base DDL operation class.
  • Implement the executeDDLInternal method in these classes to perform the necessary schema changes.

• Update the RelTableGroupSchema class to support adding and removing node table pairs.

  • Add methods to RelTableGroupSchema for adding and removing relationships between tables.

• Ensure that the new ALTER REL TABLE GROUP operations are correctly logged for durability and recovery.

  • Update the Write-Ahead Logging (WAL) system to include the new operations.

• Update the test suite to include tests for the new ALTER REL TABLE GROUP functionality.

  • Add end-to-end tests in test/ddl/e2e_ddl_test.cpp to verify that the new ALTER REL TABLE GROUP operations work as expected.

• Handle permissions and user-generated content.

  • Ensure that only authorized users can perform ALTER REL TABLE GROUP operations.
  • Update the plugin system if necessary to support the new functionality.

• Update documentation to reflect the new feature and provide examples of usage.

Remember to follow the existing codebase's style and architecture when implementing these changes.

Code snippets to check

• src/parser/transform/transform_ddl.cpp

  This file contains the logic for transforming DDL statements, including the creation of relationship table groups. Since the issue requests an ALTER statement for REL TABLE GROUP, this file is likely to be modified to include the new functionality.

• src/processor/operator/ddl/create_rel_table_group.cpp

  This file contains the execution logic for creating relationship table groups. It is relevant because the issue involves altering the REL TABLE GROUP, which may require changes to the creation logic or the addition of new logic for the ALTER statement.

• third_party/antlr4_cypher/cypher_parser.cpp

  This file is part of the parser and may need to be updated to recognize the new ALTER REL TABLE GROUP syntax.