sideconsistency

Sideconsistency is a term used in discussions of cross-domain alignment to denote the property that the two sides of a boundary remain in agreement as changes occur. A side may be a data source and a data sink, or a client and a server, or two coupled subsystems. Maintaining sideconsistency means that updates, transformations, or constraints on one side have precise, compatible effects on the other side, preserving domain invariants and avoiding contradictory states. In data integration and ETL, sideconsistency refers to ensuring that representations and constraints are preserved across mappings between schemas, and that derived data stays in sync when the source data changes. In software design, it is related to bidirectional binding, contracts, and synchronization strategies such as event sourcing or change data capture. In formal methods, it can be expressed with invariants and relation-preserving transformations. Challenges include latency, conflicts, schema evolution, heterogeneous data models, and partial updates. Techniques include explicit contracts, versioned schemas, migration policies, reconciliation rules, and testing for cross-side invariants. Relation to related concepts: consistency models, eventual consistency, bidirectional programming, lenses. Not standardized; usage varies by field.