Expand description
Traits dealing with SQLite data types.
SQLite uses a dynamic type system. Implementations of
the ToSql
and FromSql
traits are provided for the basic types that
SQLite provides methods for:
- Strings (
String
and&str
) - Blobs (
Vec<u8>
and&[u8]
) - Numbers
The number situation is a little complicated due to the fact that all
numbers in SQLite are stored as INTEGER
(i64
) or REAL
(f64
).
ToSql
and FromSql
are implemented for all primitive number types.
FromSql
has different behaviour depending on the SQL and Rust types, and
the value.
INTEGER
to integer: returns anError::IntegralValueOutOfRange
error if the value does not fit in the Rust type.REAL
to integer: always returns anError::InvalidColumnType
error.INTEGER
to float: casts usingas
operator. Never fails.REAL
to float: casts usingas
operator. Never fails.
ToSql
always succeeds except when storing a u64
or usize
value that
cannot fit in an INTEGER
(i64
). Also note that SQLite ignores column
types, so if you store an i64
in a column with type REAL
it will be
stored as an INTEGER
, not a REAL
(unless the column is part of a
STRICT table).
If the time
feature is enabled, implementations are
provided for time::OffsetDateTime
that use the RFC 3339 date/time format,
"%Y-%m-%dT%H:%M:%S.%fZ"
, to store time values as strings. These values
can be parsed by SQLite’s builtin
datetime functions. If you
want different storage for datetimes, you can use a newtype.
ToSql
and FromSql
are also implemented for Option<T>
where T
implements ToSql
or FromSql
for the cases where you want to know if
a value was NULL (which gets translated to None
).
Structs§
- Empty struct that can be used to fill in a query parameter as
NULL
.
Enums§
- Enum listing possible errors from
FromSql
trait. ToSqlOutput
represents the possible output types for implementers of theToSql
trait.- SQLite data types. See Fundamental Datatypes.
- Owning dynamic type value. Value’s type is typically dictated by SQLite (not by the caller).
- A non-owning dynamic type value. Typically the memory backing this value is owned by SQLite.
Traits§
- A trait for types that can be created from a SQLite value.
- A trait for types that can be converted into SQLite values. Returns
Error::ToSqlConversionFailure
if the conversion fails.
Type Aliases§
- Result type for implementors of the
FromSql
trait.