pub trait HasSqlType<ST>: TypeMetadata {
// Required method
fn metadata(lookup: &Self::MetadataLookup) -> Self::TypeMetadata;
}Expand description
Indicates that a SQL type exists for a backend.
§Deriving
This trait can be automatically derived by #[derive(SqlType)].
This derive will also implement NotNull and SingleValue.
When deriving this trait,
you need to specify how the type is represented on various backends.
You don’t need to specify every backend,
only the ones supported by your type.
For PostgreSQL, add #[postgres(oid = "some_oid", array_oid = "some_oid")]
or #[postgres(type_name = "pg_type_name")] if the OID is not stable.
For MySQL, specify which variant of MysqlType should be used
by adding #[mysql_type = "Variant"].
For SQLite, specify which variant of SqliteType should be used
by adding #[sqlite_type = "Variant"].
§Example
#[derive(SqlType)]
#[postgres(oid = "23", array_oid = "1007")]
#[sqlite_type = "Integer"]
#[mysql_type = "Long"]
pub struct Integer;Required Methods§
Sourcefn metadata(lookup: &Self::MetadataLookup) -> Self::TypeMetadata
fn metadata(lookup: &Self::MetadataLookup) -> Self::TypeMetadata
Fetch the metadata for the given type
This method may use lookup to do dynamic runtime lookup. Implementors
of this method should not do dynamic lookup unless absolutely necessary
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.