Module com.darkcollective.relix.symbol

Package com.darkcollective.relix.symbol.relation

Interface RelationSymbol

All Superinterfaces:

Symbol

All Known Implementing Classes:

DatabaseRelationSymbol, InlineRelationSymbol, QueryRelationSymbol, SourceRelationSymbol, SystemRelationSymbol

public sealed interface RelationSymbol
extends Symbol
permits DatabaseRelationSymbol, InlineRelationSymbol, QueryRelationSymbol, SourceRelationSymbol, SystemRelationSymbol

Sealed sub-interface of Symbol for all relation-typed symbols.

A relation symbol describes a named entity that, when evaluated, produces a set (or bag) of tuples conforming to the associated Schema.

Five concrete kinds exist:

• DatabaseRelationSymbol — backed by an external JDBC store.
• InlineRelationSymbol — rows declared inline in source.
• QueryRelationSymbol — defined by a relational algebra expression.
• SourceRelationSymbol — backed by an external HTTP, CSV, or other transport; the full source configuration lives in the semantic model.
• SystemRelationSymbol — a read-only engine-computed catalog relation in the reserved relix.* namespace.

See Also:

• Schema

Method Summary

Modifier and Type	Method	Description
Schema	schema()	The structural description of this relation's columns.

Methods inherited from interface com.darkcollective.relix.symbol.Symbol

canonicalName, declaredName, namespace, provenance, shadowPolicy

Method Details

schema

Schema schema()

The structural description of this relation's columns.

Returns:

the schema; never null