Validation

remodel-core validates models non-fatally: validate_conceptual and validate_logical return a Vec<Diagnostic> rather than an Err. The caller decides whether any finding is severe enough to block further processing. The conversion pipeline (to_logical) rejects models with one or more Severity::Error diagnostics.

Running validation

use remodel_core::validation::{validate_conceptual, validate_logical, Severity};

let diags = validate_conceptual(&m);

let has_errors = diags.iter().any(|d| d.severity == Severity::Error);
if has_errors {
    for d in &diags {
        eprintln!("[{}] {}: {}", d.severity, d.code, d.message);
    }
}

// After conversion:
let lm = m.to_logical()?;
let logical_diags = validate_logical(&lm);

Diagnostic

Constructing diagnostics

Diagnostic::error("E001", "entity has no name");
Diagnostic::warning("W001", "entity has no attributes");

Severity

Conceptual model diagnostics

W001 — entity has no attributes

Severity: Warning

Emitted for each entity that has an empty attributes list and is not a specialization child. Specialization children often inherit attributes from the parent and are exempt.

Fix: Add at least one attribute to the entity, or make it a specialization child.

E002 — entity has no primary-key attribute

Severity: Error

Emitted for each regular (non-weak, non-specialization-child) entity whose attributes contain none with is_primary = true.

Fix: Call add_primary_attribute on the entity, or set attr.is_primary = true on an existing attribute.

m.add_primary_attribute(customer, "id", DataType::Integer)?;

E003 — relationship has fewer than 2 endpoints

Severity: Error

A relationship with 0 or 1 endpoints is structurally invalid (it connects nothing). The minimum is 2.

Fix: Call .with(entity, cardinality) at least once when building the relationship.

E004 — relationship references unknown entity

Severity: Error

One of the relationship's endpoints refers to an EntityId that does not exist in the model. This typically occurs when an entity was removed after the relationship was created, or when deserializing a corrupt file.

Fix: Remove or correct the stale endpoint.

Logical model diagnostics

L001 — table has no columns

Severity: Error

A Table with an empty columns map cannot produce valid DDL.

L002 — table has no primary key

Severity: Warning

A table without a PRIMARY KEY constraint is valid SQL in most dialects but is an antipattern. The converter always synthesises a primary key, so this warning only appears when you build a LogicalModel manually.

L003 — FK references unknown table

Severity: Error

A ForeignKey constraint refers to a TableId that does not exist in the model.

L004 — FK arity mismatch

Severity: Error

A ForeignKey constraint has a different number of local columns (columns) than referenced columns (references_columns). The arity must match for the FK to be valid.

Integration pattern

fn compile(m: &ConceptualModel) -> remodel_core::Result<String> {
    let diags = remodel_core::validation::validate_conceptual(m);

    // Surface all findings
    for d in &diags {
        match d.severity {
            Severity::Error   => eprintln!("ERROR   {} – {}", d.code, d.message),
            Severity::Warning => eprintln!("WARN    {} – {}", d.code, d.message),
            Severity::Info    => println!( "INFO    {} – {}", d.code, d.message),
        }
    }

    // Block on errors
    if diags.iter().any(|d| d.severity == Severity::Error) {
        return Err(remodel_core::Error::ConversionError(
            "model has validation errors".into()
        ));
    }

    let lm = m.to_logical()?;
    Ok(lm.to_sql(remodel_core::sql::SqlDialect::Postgres))
}