This code is inspired by a paper on shredding.
Cheney, James, Sam Lindley, and Philip Wadler. "Query shredding: efficient relational evaluation of queries over nested multisets." Proceedings of the 2014 ACM SIGMOD international conference on Management of data. ACM, 2014.
Abstract: Nested relational query languages have been explored extensively, and underlie industrial language-integrated query systems such as Microsoft's LINQ. However, relational databases do not natively support nested collections in query results. This can lead to major performance problems: if programmers write queries that yield nested results, then such systems typically either fail or generate a large number of queries. We present a new approach to query shredding, which converts a query returning nested data to a fixed number of SQL queries. Our approach, in contrast to prior work, handles multiset semantics, and generates an idiomatic SQL:1999 query directly from a normal form for nested queries. We provide a detailed description of our translation and present experiments showing that it offers comparable or better performance than a recent alternative approach on a range of examples.
Translate nested queries expressed as om.next queries into regular SQL queries.
The core issue is that sql queries aren't great at nested data. They return tables of information, not graphs.
The approach taken is:
- Shred the nested query up into a set of regular sql queries
- Execute the sql queries
- Stitch the results into the nested structure
Shredding: work in progress but seems to be looking good.
Executing: no code
Stitching: no code