Sylin.Koan.Data.Relational

Koan.Data.Relational

Adapter-agnostic relational schema + LINQ translator used by providers like Koan.Data.Connector.Sqlite and Koan.Data.Connector.SqlServer.

• Contracts: IRelationalDialect, IRelationalSchemaModel, IRelationalSchemaSynchronizer
• LINQ translator hooks: ILinqSqlDialect, LinqWhereTranslator<TEntity>, RelationalCommandCache

Capabilities

• Build table/index models from entity annotations
• Add-only schema synchronization (create table/index)
• Minimal LINQ-to-SQL pushdown for simple predicates and projections

LINQ (minimal translator)

An intentionally small LINQ-to-SQL helper lives in Linq/:

• ILinqSqlDialect: tiny hooks the translator needs (identifier quoting, LIKE escaping, parameter naming).
• LinqWhereTranslator<TEntity>: translates a restricted subset of predicate expressions to a WHERE clause and parameters.
• RelationalCommandCache: caches select lists per (entity, dialect) to avoid repeated string building.

Providers can implement ILinqSqlDialect (in addition to schema IRelationalDialect) to enable pushdown. Unsupported expressions should throw NotSupportedException; callers should fallback to in-memory filtering.

• Builder: RelationalModelBuilder.FromEntity(typeof(TEntity)) builds a table model from annotations
• Synchronizer: EnsureCreated(dialect, model, connection) emits CREATE TABLE + INDEX statements (add-only)

Notes:

• Provider-specific SQL grammar belongs in the provider (e.g., SqliteDialect in Koan.Data.Connector.Sqlite).
• Complex CLR types map to JSON-encoded TEXT columns; simple types map to native types.

References

• Data access reference: ~/reference/data-access.md
• Decision DATA-0061: ~/decisions/DATA-0061-data-access-pagination-and-streaming.md