field name for relationship {relationship_name} of type {typ

Error message

field name for relationship {relationship_name} of type {type_name} conflicts with the existing field {field_name}

What it means

Schema-build error specifically for relationships: the field name configured (or defaulted) for a relationship on an object type collides with a field that already exists on that type (e.g. a column field). The relationship cannot be added without overwriting an existing field.

Source

Thrown at v3/crates/graphql/schema/src/lib.rs:326

        "internal error while building schema, role {role} not found in argument presets for model {model_name}"
    )]
    InternalModelArgumentPresetLookupFailure {
        model_name: Qualified<ModelName>,
        role: Role,
    },
    #[error(
        "internal error while building schema, role {role} not found in argument presets for command {command_name}"
    )]
    InternalCommandArgumentPresetLookupFailure {
        command_name: Qualified<CommandName>,
        role: Role,
    },
    #[error("duplicate field name {field_name} generated while building object type {type_name}")]
    DuplicateFieldNameGeneratedInObjectType {
        field_name: ast::Name,
        type_name: Qualified<CustomTypeName>,
    },
    #[error(
        "field name for relationship {relationship_name} of type {type_name} conflicts with the existing field {field_name}"
    )]
    RelationshipFieldNameConflict {
        relationship_name: RelationshipName,
        field_name: ast::Name,
        type_name: Qualified<CustomTypeName>,
    },
    #[error(
        "the aggregation function {field_name} conflicts with the aggregatable field {field_name} in the aggregate expression {aggregate_expression} is named {field_name}. Either rename the aggregation function or the field"
    )]
    AggregationFunctionFieldNameConflict {
        aggregate_expression: Qualified<AggregateExpressionName>,
        field_name: ast::Name,
    },
    #[error(
        "internal error: duplicate aggregatable field {field_name} in the aggregate expression {aggregate_expression} is named {field_name}"
    )]
    InternalDuplicateAggregatableField {

View on GitHub (pinned to 724551b9ae)

Solutions

Rename the relationship (or set its GraphQL field name) in metadata so it differs from the existing field
Alternatively rename/override the conflicting column's field name
Check for duplicate relationship definitions targeting the same field name

Example fix

# before (metadata yaml)
relationships:
  author: ...
# with a column also named author
# after
relationships:
  writer: ...
  # or map the column to a different field name

Defensive patterns

Strategy: validation

Validate before calling

// Before build: relationship names must not collide with the model's field names
let field_names: HashSet<&str> = model_fields(model);
for rel in &model.relationships {
    assert!(!field_names.contains(rel.field_name()), "relationship {} conflicts", rel.name());
}

Try / catch

// Catch Error::RelationshipFieldNameConflict { relationship_name, field_name, .. } and rename the relationship in metadata

Prevention

Prefix relationship names distinctly from columns
Validate metadata in CI with a schema build

When it happens

Trigger: Metadata defines a relationship on a model whose name (or mapped field name) equals an existing field of the same object type — commonly a column or another relationship with the same name.

Common situations: Relationship named identically to a column (e.g. both `author`), renaming fields in metadata so they clash, foreign-key relationships defaulting to the same name as a column.

Related errors

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/1763a4941994f7f4. Report an issue: GitHub.