Unresolved relationship tables giving avoidable binding errors (hashtag2812)

[vikramsubramanian]

I have a database with an RDFGraph TurtleTest, a regular node table Student, and a regular rel table st_r from student to TurtleTest_r resource node table. I get the following error:

kuzu> match (a)-[e]->(b:TurtleTest_l) return *;
Error: Binder exception: Relationship pattern e contains both property graph relationship label st_to_r and RDFGraph label TurtleTest. Mixing two tables in the same relationship pattern is not supported.
kuzu> call show_tables() return *;

I should not be getting this because the destination of e is TurtleTest_l, so e can only bind to TurtleTest_lt. So there is no real mixing of relationship tables from RDFGraph and regular property graph. We should not disable all multilabel queries because a database has an rdfgraph and a regular relationship table. We should only disable it when a relationship pattern resolves to mix these two types of relationship tables.

Here is a more basic example that we re disabling unlabeled or multilabel queries completely: I have a database with an RDFGraph TestTurtle, a regular node table student, and a regular rel table st_to_st from student to student.

kuzu> create rel table st_to_st (from student to student);
-----------------------------------------
| result                                |
-----------------------------------------
| Rel table: st_to_st has been created. |
-----------------------------------------
 match (a)-[e]->(b:TurtleTest_l) return *;
Error: Binder exception: Relationship pattern e contains both property graph relationship label st_to_st and RDFGraph label TurtleTest. Mixing two tables in the same relationship pattern is not supported.

So as long as there is a regular relationship in the database we give this error even though there is no relationship table between an RDFGraph's node table and a regular node table. )

[mayil-ai[bot]]

Summary: The issue involves avoidable binding errors with unresolved relationship tables, causing a mix of RDFGraph and regular property graph relationship tables.

Possible Solution

Based on the provided information and code snippets, the issue seems to be related to the handling of relationship patterns in queries, particularly when involving RDFGraphs and property graphs. The error message indicates that the system does not support mixing two tables in the same relationship pattern, which is happening in the command match (a)-[e]->(b:TurtleTest_l) return *;.

To resolve the issue, consider the following steps:

• Review the logic in src/binder/bind/bind_graph_pattern.cpp where the relationship patterns are bound and validated. Specifically, look at the bindQueryRel function, which is responsible for binding relationship patterns in the query graph.
• Ensure that the bindQueryRel function correctly distinguishes between RDFGraph relationships and property graph relationships, and that it does not allow a mix of both in the same pattern unless explicitly supported by the system.
• Modify the validation logic to allow for multilabel queries if they do not actually mix RDFGraph and property graph relationship tables. This might involve adjusting the checks performed in the if (!resourceTableIDs.empty()) block, where the exception is thrown for multiple RDF table labels.
• Update the error message to be more descriptive if the mix is indeed unsupported, or adjust the logic to allow the query if the system can support it.
• Add or modify unit tests in test/ddl/e2e_ddl_test.cpp to cover the scenario where a relationship pattern contains labels from both RDFGraph and property graphs, ensuring that the system behaves as expected after the changes.
• After making the changes, run the full test suite to ensure that no other parts of the system are affected by the modifications.

Remember to follow the project's coding standards and guidelines for contributing to the codebase when making changes.

Code snippets to check

• src/binder/bind/bind_graph_pattern.cpp

  This file contains logic related to binding graph patterns, which is directly related to the issue of relationship patterns containing mixed labels from RDFGraph and property graph tables.