> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wazoo.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Relational Databases

> Worlds vs Relational Databases: RDF fact ledger vs SQL tables.

## At a glance

|                 | Worlds                                                | Relational Databases ([Postgres](https://www.postgresql.org), [MySQL](https://dev.mysql.com/doc/), [SQLite](https://www.sqlite.org/docs.html)) |
| :-------------- | :---------------------------------------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------- |
| Primary role    | Authoritative RDF fact ledger & SPARQL context engine | General-purpose relational data management                                                                                                     |
| Data model      | RDF triples/quads in an append-only graph ledger      | Normalised SQL tables, rows, and foreign keys                                                                                                  |
| Schema rigidity | Flexible graph triples with SHACL shape validation    | Fixed table schemas requiring DDL migrations                                                                                                   |
| Retrieval       | SPARQL graph queries, full-text, & vector fusion      | SQL queries with JOINs, indexes, & aggregations                                                                                                |
| Deployment      | Edge-ready adapters (LibSQL, Postgres) or Cloud       | Self-hosted or managed database instances                                                                                                      |

## Overlap and shared capabilities

Both Worlds and relational databases provide ACID-compliant data persistence and
structured queries. In fact, Worlds can persist its RDF quad ledger directly to
relational backends like Postgres or LibSQL via adapters (`worlds-postgres`,
`worlds-libsql`).

The structural difference:

* Relational databases require rigid table schemas and explicit foreign-key
  JOINs, making arbitrary multi-hop relationship discovery complex.
* Worlds models data as flexible RDF graph triples. Relationships are
  first-class entities that can be traversed dynamically via SPARQL without
  schema migrations.

## When Worlds fits

* You are storing dynamic, evolving domain facts and agent memories where schema
  rigidity is a bottleneck.
* You need multi-hop graph queries (SPARQL) to verify connected facts.
* You require hybrid vector + full-text + graph retrieval fused via Reciprocal
  Rank Fusion.

## When Relational Databases fit

* You are managing standard OLTP application data (user accounts, orders,
  transactions).
* You require fixed table schemas and established SQL tooling.
* You are building core relational infrastructure before adding an AI context
  layer.