Cohesive.Relations 0.1.0-alpha.78

Cohesive.Relations

Cohesive.Relations lets applications describe relationships, projections, filters, and queries in typed C# while leaving storage placement and execution strategy to compilers and adapters.

Install

dotnet add package Cohesive.Relations

Author a relation

A complete Load -> LoadDto relation needs no hand-authored node IDs, binding names, source placement, or adapter configuration:

var author = RelationQuery.Expression();
var loads = author.Source<Load>();

var loadDtos = author.Project(
    loads,
    (Load load) => new LoadDto
    {
        Id = load.Id,
        Status = load.Status
    });

var relation = loadDtos.BuildRelation(dto => dto.Id);

The authoring session derives the logical nodes, bindings, shapes, field assignments, relation identity, display name, and provenance. relation contains the canonical definition and structured validation diagnostics.

Add a relationship when the result needs another fact:

var author = RelationQuery.Expression();
var loads = author.Source<Load>();

var customers = author.Traverse<Load, Customer>(
    loads,
    load => load.CustomerId);

var searchDocuments = author.Project(
    customers,
    (Load load, Customer customer) => new LoadSearchDto
    {
        Id = load.Id,
        CustomerName = customer.Name
    });

var loadSearch = searchDocuments.BuildRelation(dto => dto.Id);

The same traversal may become an in-memory lookup, a PostgreSQL join, bounded source reads followed by local correlation, or another capability-compatible realization. The relation itself does not change.

Use it for

• DTO mapping and enrichment.
• Independently invoked row and aggregation queries.
• Application read models, API results, integration payloads, and reports.
• Field-demand, dependency, lineage, and missing-input analysis.
• Relation-derived materialized views and targeted rebuild planning.
• Portable execution across supplied objects and registered physical sources.

How execution stays honest

The canonical relation/query document is the semantic authority. An invocation selects results and parameters; compilation derives the exact fields and operations it needs. A target must prove those requirements against its capabilities and operating boundaries. Unsupported semantics and incomplete source evidence produce structured diagnostics rather than a weakened query or a misleading empty result.

The expression API is the normal application surface. Structural authoring and direct IR construction remain available for importers, generators, persistence tooling, and compiler tests.

Continue

• Getting started builds, evaluates, and enriches a relation.
• Execution and adapters covers supplied facts, acquisition, placement, and native compilation.
• Diagnostics explains incomplete evidence and requirement gaps.
• Capability reference is generated from the implemented target profiles.
• Migration covers the retired relation-query stack.
• Internals retains the complete semantic model, compiler architecture, use cases, and design rationale.

Adapter-specific guides are available for Cohesive.Adapters.Postgres, Cohesive.Adapters.Cosmos, and Cohesive.Adapters.Elastic.