Conversions between Rust and standard SQL types.
| Rust type | SQL type(s) |
bool | BOOLEAN |
i16 | SMALLINT |
i32 | INT |
i64 | BIGINT |
f32 | FLOAT |
f64 | DOUBLE |
&str, String | VARCHAR, CHAR, TEXT |
In addition, Option<T> is supported where T implements Type. An Option<T> represents
a potentially NULL value from SQL.