diesel-rs/diesel · error

Failed to create trigger

Error message

Failed to create trigger

What it means

Registering the `diesel_manage_updated_at` helper failed while executing its trigger-creating SQL. The offending input is the SQLite connection or database schema state that rejected the trigger creation.

Solutions

1. Ensure the database is writable and not locked
2. Check for a conflicting trigger on the target table
3. Register the function outside an active transaction if required

When it happens

Trigger: Thrown at diesel/src/sqlite/connection/mod.rs:1750 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of diesel-rs/diesel@6fa6ed01b2 (2026-09-07). Data as JSON: /api/errors/15b88133492eb980. Report an issue: GitHub.

Appendix: source

Thrown at diesel/src/sqlite/connection/mod.rs:1750

        })
    }

    fn register_diesel_sql_functions(&self) -> QueryResult<()> {
        use crate::sql_types::{Integer, Text};

        // This function has side effects (creates triggers), so it should not
        // be deterministic. We use DIRECTONLY to prevent it from being called
        // from malicious schema objects in untrusted databases.
        functions::register::<Text, Integer, _, _, _>(
            &self.raw_connection,
            "diesel_manage_updated_at",
            SqliteFunctionBehavior::DIRECTONLY,
            |conn, table_name: String| {
                conn.exec(&alloc::format!(
                    include_str!("diesel_manage_updated_at.sql"),
                    table_name = table_name
                ))
                .expect("Failed to create trigger");
                0 // have to return *something*
            },
        )
    }

    fn establish_inner(database_url: &str) -> Result<SqliteConnection, ConnectionError> {
        use crate::result::ConnectionError::CouldntSetupConfiguration;
        let raw_connection = RawConnection::establish(database_url)?;
        let conn = Self {
            statement_cache: StatementCache::new(),
            raw_connection,
            transaction_state: AnsiTransactionManager::default(),
            metadata_lookup: (),
            instrumentation: DynInstrumentation::none(),
            serialized_data: Vec::new(),
        };
        conn.register_diesel_sql_functions()
            .map_err(CouldntSetupConfiguration)?;

View on GitHub (pinned to 6fa6ed01b2)