Renormalize - The sequel to SQL

Relational databases are pretty useful but:

• Joins are slow, even with lots of indexes and a great optimizer.
• ORMs hide but don't eliminate joins.

Document stores

• Natively handle objects, but,
• Abandon the idea of querying the data using a language.

The Akiban Database Server fundamentally solves the join problem and unifies the two worlds.

The basic idea

• Table groups assemble sets of tables into a new logical construct called table-groups. Table groups are a good match for your intuitive notions about what is related to what, i.e., mirror application objects.
• New physical organization: Store the joined rows of a table-group interleaved in a b-tree. E.g. a Customer is followed by its Orders. Each Order is followed by its items. Record keys are constructed so that insertion into the b-tree maintains this interleaving.
• The join is now precomputed, and joins that used to be expensive are essentially free. The rows of the join are consecutive b-tree records.
• ORMs can now request, for example, a Customer with all of its Orders and Items. A connection setting instructs the server to return the result as a JSON-structured object. Voila, a Customer its Orders and Items in one round trip, with the join computed for the cost of one b-tree probe on the server.
• Powerful indexing on a table group is now possible. Indexes combining columns from related tables, as well as intersecting indexes from different tables are both possible. e.g., you can create an index on (customer.name, order.date), as well as intersect indexes on customer.address and on item.sku, because they both map to rows in the same group.

What this means

• Table-group interleaving reflects intuitive understanding of objects/documents.
• Documents can be accessed in a single request. ORMs can leverage this for efficient interaction between ORM and database.
• Joins within a group are close to free. Complex queries often run 10x-150x faster in memory (compared to MySQL). Denormalization is not necessary.
• The perfect synthesis of documents and SQL.