Types

Field Manual Section 4 - Payload Specs

Tank brings a full type arsenal to the field. The Entity derive macro identifies the type you're using by inspecting its final path segment (the "trailer"). For example, std::collections::VecDeque, collections::VecDeque, or simply VecDeque all resolve to the same list type.

Tank maps ordinary Rust types (numbers, strings, times, collections) to the closest column types each driver supports, falling back to generic representations when appropriate. Below is the standard mapping of Rust types to each driver's column type. :x: indicates no native support at this time. Collection types may be emulated in some drivers using generic JSON/text representations.

Column Types

Rust	DuckDB	SQLite	Postgres	MySQL
bool	BOOLEAN	INTEGER	BOOLEAN	BOOLEAN
i8	TINYINT	INTEGER	SMALLINT	TINYINT
i16	SMALLINT	INTEGER	SMALLINT	SMALLINT
i32	INTEGER	INTEGER	INTEGER	INTEGER
i64	BIGINT	INTEGER	BIGINT	BIGINT
i128	HUGEINT	❌	NUMERIC(38)	NUMERIC(38)
u8	UTINYINT	INTEGER	SMALLINT	TINYINT UNSIGNED
u16	USMALLINT	INTEGER	INTEGER	SMALLINT UNSIGNED
u32	UINTEGER	INTEGER	BIGINT	INTEGER UNSIGNED
u64	UBIGINT	INTEGER	NUMERIC(19)	BIGINT UNSIGNED
u128	UHUGEINT	❌	NUMERIC(38)	NUMERIC(38) UNSIGNED
isize	BIGINT ⚠️	INTEGER	NUMERIC(38)	BIGINT ⚠️
usize	UBIGINT ⚠️	INTEGER	NUMERIC(38)	BIGINT UNSIGNED ⚠️
f32	FLOAT	REAL	REAL	FLOAT
f64	DOUBLE	REAL	DOUBLE	DOUBLE
rust_decimal::Decimal	DECIMAL	REAL	NUMERIC	NUMERIC
tank::FixedDecimal<W, S>	DECIMAL(W,S)	REAL	NUMERIC(W,S)	NUMERIC(W,S)
char	CHAR(1)	TEXT	CHAR(1)	CHAR(1)
String	TEXT	TEXT	TEXT	TEXT
Box<[u8]>	BLOB	BLOB	BYTEA	BLOB
time::Date	DATE	TEXT ⚠️	DATE	DATE
time::Time	TIME	TEXT ⚠️	TIME	TIME
time::PrimitiveDateTime	TIMESTAMP	TEXT ⚠️	TIMESTAMP	DATETIME
time::OffsetDateTime	TIMESTAMPTZ	TEXT ⚠️	TIMESTAMPTZ	TIMESTAMP
std::time::Duration	INTERVAL	❌	INTERVAL	❌
time::Duration	INTERVAL	❌	INTERVAL	❌
tank::Interval	INTERVAL	❌	INTERVAL	❌
uuid::Uuid	UUID	TEXT	UUID	CHAR(36)
[T; N]	T[N]	❌	T[N]	JSON
Vec<T>	T[]	❌	T[]	JSON
VecDeque<T>	T[]	❌	T[]	JSON
LinkedList<T>	T[]	❌	T[]	JSON
HashMap<K, V>	MAP(K,V)	❌	❌	JSON
BTreeMap<K, V>	MAP(K,V)	❌	❌	JSON

WARNING

When a type falls back to a generic representation (e.g. TEXT or JSON), Tank encodes it predictably so equality / ordering comparisons (where meaningful) behave as expected. Advanced indexing or operator support may vary by driver.

The special size types maps to the corresponding 64 bits integer or 32 bits integer depending on the size.

Wrapper Types

Beyond the standard munitions listed above, Tank supports a range of wrapper types you can deploy directly in your entities. The resulting SQL type is inferred from the inner payload your wrapper carries into battle.

Supported wrappers:

• tank::Passive<T>: Omit on update / allow default generation on insert.
• Option<T>: Nullable column.
• Box<T>
• Cell<T>
• RefCell<T>
• RwLock<T>
• Arc<T>
• Rc<T>

With this arsenal, your entities hit every target, every time.