hasura/graphql-engine · error · NDCValidationError

function {function_name} is not defined in data connector {d

Error message

function {function_name} is not defined in data connector {db_name}

What it means

Thrown during metadata resolution when a Command is configured to call a function that the target data connector's schema does not expose. The resolver cross-checks every function referenced in command definitions against the NDC connector's capability/schema response.

Source

Thrown at v3/crates/metadata-resolve/src/helpers/ndc_validation.rs:59

        argument_name: DataConnectorArgumentName,
    },
    #[error(
        "column {column_name} is not defined in collection {collection_name} in data connector {db_name}"
    )]
    NoSuchColumn {
        db_name: Qualified<DataConnectorName>,
        model_name: Qualified<ModelName>,
        field_name: FieldName,
        collection_name: CollectionName,
        column_name: DataConnectorColumnName,
    },
    #[error("procedure {procedure_name} is not defined in data connector {db_name}")]
    NoSuchProcedure {
        db_name: Qualified<DataConnectorName>,
        command_name: Qualified<CommandName>,
        procedure_name: ProcedureName,
    },
    #[error("function {function_name} is not defined in data connector {db_name}")]
    NoSuchFunction {
        db_name: Qualified<DataConnectorName>,
        command_name: Qualified<CommandName>,
        function_name: FunctionName,
    },
    #[error(
        "column {column_name} is not defined in function/procedure {func_proc_name} in data connector {db_name}"
    )]
    NoSuchColumnForCommand {
        db_name: Qualified<DataConnectorName>,
        command_name: Qualified<CommandName>,
        field_name: FieldName,
        func_proc_name: String,
        column_name: DataConnectorColumnName,
    },
    #[error(
        "column {column_name} has type {column_type} in collection {collection_name} in data connector {db_name}, not type {field_type}"
    )]

View on GitHub (pinned to 724551b9ae)

Solutions

1. Verify the function exists in the data connector (query the database or the connector's /schema endpoint) and correct the function name in the Command definition
2. Reload/refresh the data connector's schema cache if the function was recently created
3. Align the metadata's function name with the connector's actual exported function name

Example fix

# before
kind: Command
spec:
  target:
    function:
      name: get_user_by_email  # does not exist in connector
# after
kind: Command
spec:
  target:
    function:
      name: getUserByEmail   # matches connector schema

// before resolving, check the function exists in the connector schema
let exists = connector_schema.functions.iter().any(|f| f.name == metadata_function_name);

When it happens

Trigger: Defining a Command with a CommandFunction target where function_name does not exist in the data connector's reported functions; using a stale connector schema after the function was renamed/dropped in the underlying database.

Common situations: Function renamed or dropped in the database without updating the metadata; typo in function name in the YAML metadata; connector schema cache out of date; promoting metadata between environments with different DB schemas.

Related errors

• unable to parse server endpoint: %w
• column {column_name} is not defined in function/procedure {f
• NDC validation error: {0}
• unknown target command {command_name:} used in relationship
• target argument {argument_name} in argument mapping for rela

AI-assisted analysis of hasura/graphql-engine@724551b9ae (2026-08-28). Data as JSON: /api/errors/d90671f32f75d4e3. Report an issue: GitHub.