digraph NaiveDatabase {
    rankdir=TB;
    node [shape=record, fontname="Helvetica", fontsize=10];
    edge [fontname="Helvetica", fontsize=9];

    // Main database
    NaiveDatabase [label="{NaiveDatabase|relations : Map RelationId Relation\lconstants : Set Constant\l}"];

    // Core data types
    Relation [label="{Relation|_name : Text\l_arity : Int\l_tuples : Set [Constant]\l_rules : [RelationRule]\l}"];

    RelationRule [label="{RelationRule|headVariables : [Text]\lbody : [(Relation, [RuleElement])]\l}"];

    RuleElement [label="{RuleElement|RuleElementConstant Constant\l| RuleElementVariable Text\l}"];

    // Constraint types (used during rule processing)
    ConstraintElement [label="{ConstraintElement|ConstraintElementConstant Constant\l| ConstraintElementIndex Int\l}"];

    BodyConstraint [label="{BodyConstraint|_relation : Relation\l_elements : [ConstraintElement]\l}"];

    RuleContext [label="{RuleContext|__relation : Relation\l_headVariables : [RuleElement]\l_bodyConstraints : [BodyConstraint]\l_db : NaiveDatabase\l}"];

    // Type aliases (shown as notes)
    TypeAliases [shape=note, label="Type Aliases\l\lConstant = Term\lRelationId = Text\l"];

    // Value type (standalone)
    Value [label="{Value|ValueInt Int\l| ValueSymbol String\l}"];

    // Exception type
    NaiveDatabaseException [label="{NaiveDatabaseException|CannotParseStatementException\l| NonFactException\l| NonRuleException\l| NonQueryException\l| BadArityException\l| VariableLookupException\l| UnexpectedConstantException\l}"];

    // Relationships
    NaiveDatabase -> Relation [label="contains *", style=solid];
    Relation -> RelationRule [label="has *", style=solid];
    RelationRule -> Relation [label="references *", style=dashed];
    RelationRule -> RuleElement [label="contains *", style=solid];

    BodyConstraint -> Relation [label="references", style=dashed];
    BodyConstraint -> ConstraintElement [label="contains *", style=solid];

    RuleContext -> Relation [label="references", style=dashed];
    RuleContext -> RuleElement [label="contains *", style=solid];
    RuleContext -> BodyConstraint [label="contains *", style=solid];
    RuleContext -> NaiveDatabase [label="references", style=dashed];

    // Grouping
    subgraph cluster_core {
        label="Core Types";
        style=rounded;
        color=blue;
        NaiveDatabase; Relation; RelationRule; RuleElement;
    }

    subgraph cluster_processing {
        label="Rule Processing";
        style=rounded;
        color=green;
        RuleContext; BodyConstraint; ConstraintElement;
    }

    subgraph cluster_other {
        label="Other";
        style=rounded;
        color=gray;
        Value; NaiveDatabaseException; TypeAliases;
    }
}