[Feature Request] Add advanced ANN query options in oceanbase

[fengju0213]

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Motivation

ObVecClient ann_search supports multiple distance functions (l2_distance,cosine_distance, inner_product, negative_inner_product) and SQLAlchemy where_clause filtering, but OceanBaseStorage.query() currently exposes only l2/cosine and does not allow filters.

Solution

• Extend distance to include inner_product and negative_inner_product and map them
  to the corresponding SQLAlchemy functions.
  • Add an optional where_clause parameter to OceanBaseStorage.query() and pass it
    through to ann_search.
  • Update OceanBase storage docs and example code to show a filtered ANN query using
    sqlalchemy.text or SQLAlchemy expressions.

reference: https://www.oceanbase.com/docs/common-oceanbase-database-cn-1000000004476154#8-title-DML%20%E6%93%8D%E4%BD%9C

Alternatives

No response

Additional context

No response

[YixinZ-NUS]

Hi team, I discovered this via the OceanBase Developer Activities. I've reviewed the issue and I'm interested in working on it. Could you please assign me?