RelDiff: Relational Data Generative Modeling with Graph-Based Diffusion Models

TL;DR

RelDiff is a new diffusion-based generative model that synthesizes complete relational databases by explicitly modeling their graph structure, improving realism and structural integrity over previous methods.

Contribution

It introduces a novel diffusion model that explicitly captures relational graph structures for generating synthetic databases, addressing limitations of prior flat-table approaches.

Findings

Outperforms prior methods on 11 benchmark datasets

Produces more realistic and coherent synthetic relational data

Maintains high fidelity and referential integrity

Abstract

Real-world databases are predominantly relational, comprising multiple interlinked tables that contain complex structural and statistical dependencies. Learning generative models on relational data has shown great promise in generating synthetic data and imputing missing values. However, existing methods often struggle to capture this complexity, typically reducing relational data to conditionally generated flat tables and imposing limiting structural assumptions. To address these limitations, we introduce RelDiff, a novel diffusion generative model that synthesizes complete relational databases by explicitly modeling their foreign key graph structure. RelDiff combines a joint graph-conditioned diffusion process across all tables for attribute synthesis, and a $2K+$SBM graph generator based on the Stochastic Block Model for structure generation. The decomposition of graph structure and relational attributes ensures both high fidelity and referential integrity, both of which are crucial aspects of synthetic relational database generation. Experiments on 11 benchmark datasets demonstrate that RelDiff consistently outperforms prior methods in producing realistic and coherent synthetic relational databases. Code is available at https://github.com/ValterH/RelDiff.