What causes "Failed to get small integer" in SeaQL/sea-orm?

Declare the field as `Option ` if the column is nullable, or add a NOT NULL constraint

Failed to get small integer

Error message

Failed to get small integer

What it means

In `ProxyRow`, `SMALLINT` MySQL columns are read via `row.try_get::<i16>` and unwrapped with `.expect("Failed to get small integer")`. If the value cannot be decoded as i16 — most commonly because it is NULL, or the underlying value has a different type than the described metadata — the expect panics with this message.

Source

Thrown at src/driver/sqlx_mysql.rs:421

                        "SMALLINT UNSIGNED" => Value::SmallUnsigned(
                            row.try_get(c.ordinal())
                                .expect("Failed to get unsigned small integer"),
                        ),
                        "INT UNSIGNED" => Value::Unsigned(
                            row.try_get(c.ordinal())
                                .expect("Failed to get unsigned integer"),
                        ),
                        "MEDIUMINT UNSIGNED" | "BIGINT UNSIGNED" => Value::BigUnsigned(
                            row.try_get(c.ordinal())
                                .expect("Failed to get unsigned big integer"),
                        ),
                        "TINYINT" => Value::TinyInt(
                            row.try_get(c.ordinal())
                                .expect("Failed to get tiny integer"),
                        ),
                        "SMALLINT" => Value::SmallInt(
                            row.try_get(c.ordinal())
                                .expect("Failed to get small integer"),
                        ),
                        "INT" => {
                            Value::Int(row.try_get(c.ordinal()).expect("Failed to get integer"))
                        }
                        "MEDIUMINT" | "BIGINT" => Value::BigInt(
                            row.try_get(c.ordinal()).expect("Failed to get big integer"),
                        ),
                        "FLOAT" => {
                            Value::Float(row.try_get(c.ordinal()).expect("Failed to get float"))
                        }
                        "DOUBLE" => {
                            Value::Double(row.try_get(c.ordinal()).expect("Failed to get double"))
                        }

                        "BIT" | "BINARY" | "VARBINARY" | "TINYBLOB" | "BLOB" | "MEDIUMBLOB"
                        | "LONGBLOB" => Value::Bytes(
                            row.try_get::<Option<Vec<u8>>, _>(c.ordinal())
                                .expect("Failed to get bytes")

View on GitHub (pinned to e29bcd1b41)

Solutions

Declare the field as `Option<i16>` if the column is nullable, or add a NOT NULL constraint
Regenerate the entity from the live schema to match the real column type
Fix mock/proxy test data to return `i16` values for SMALLINT columns
Remove SELECT-list expressions (COALESCE/CAST) that alter the column's reported type

Example fix

// before
pub rank: i16,
// after
pub rank: Option<i16>,

Defensive patterns

Strategy: validation

Validate before calling

// Verify SMALLINT columns before decoding
SELECT COLUMN_TYPE, IS_NULLABLE FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ? AND COLUMN_NAME = ?;
// expect COLUMN_TYPE = 'smallint', IS_NULLABLE = 'NO'

Type guard

fn is_i16_compatible(col_type: &str, nullable: bool, value_is_null: bool) -> bool {
    col_type.eq_ignore_ascii_case("smallint") && !nullable && !value_is_null
}

Prevention

Use Option<i16> for nullable smallint fields
Check LEFT JOINs that introduce NULLs into otherwise NOT NULL columns
Keep proxy mock data as i16 for SMALLINT columns
Regenerate entities after migrations

When it happens

Trigger: A SMALLINT column containing NULL in a result set decoded through the proxy driver, or metadata/actual-type mismatch (e.g. column altered to SMALLINT UNSIGNED or INT after description).

Common situations: Nullable smallint columns joined via LEFT JOIN yielding NULL; schema drift after migrations; proxy-driver mock rows returning i32/u16 for a column described as SMALLINT.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

AI-assisted analysis of SeaQL/sea-orm@e29bcd1b41 (2026-09-10). Data as JSON: /api/errors/e53d9abe54b95798. Report an issue: GitHub.