Postgres

The community member is working with PGVectorStore and has data already uploaded to PostgreSQL. They want to know if they can create indexes on existing tables, as the documentation mainly covers uploading documents and creating indexes. The community members have not found a solution for this use case yet. Another community member responds that using an existing PostgreSQL database is something they haven't figured out how to do yet, and suggests that the community member submit a PR if they have ideas on how to do this. The community member also asks for more detailed documentation on the methods and objects available for VectorStoreIndex, as they've only found information on the VectorStoreIndex.from_documents method. A final community member suggests reading the source code for more information.