8 breaking releases
0.9.0 | Oct 18, 2024 |
---|---|
0.7.0 | Sep 2, 2024 |
#10 in #redb
381 downloads per month
Used in redb_model
29KB
636 lines
Redb Model
A derive macro for generating [redb] table definitions and (optionally) DTO object conversion methods/implementations.
Functionality
At a minimum, deriving Model
on a named struct
will implement the [Model]
trait, declaring redb::TableDefinition
as an associated constant.
#[derive(Model)]
struct User {
#[entry(position(key))]
id: u32,
#[entry(position(value))]
name: String,
#[entry(position(value))]
email: String,
}
assert_eq!(User::DEFINITION.name(), "User");
Tables can be customized with optional arguments, and an implementation of
[ModelExt] can be generated to provide common DTO
functionality.
#
#[derive(Model)]
#[model(name = "outbound_edge", impl_ext)]
struct Edge {
#[entry(position(key))]
source: u32,
#[entry(position(key))]
target: u32,
#[entry(position(value))]
label: String,
}
assert_eq!(Edge::DEFINITION.name(), "outbound_edge");
let edge = Edge::from_values(((0, 1), "label".to_owned()));
let txn = db.begin_write().unwrap();
{
let mut table = txn.open_table(Edge::DEFINITION).unwrap();
let (k, v) = edge.as_values();
table.insert(k, v).unwrap();
}
txn.commit().unwrap();
Struct Attributes
A model can be customized with the model
attribute, providing any of the
following arguments:
Argument | Description | Type | Default |
---|---|---|---|
table_name |
The table name passed to the definition | String |
<Struct name> (case-sensitive) |
table_type |
Table type, either table or multimap_table |
String |
table |
impl_ext |
Implement ModelExt for the type |
bool |
false |
impl_from |
Implement From<T> , mapping T to the from_values(T) and from_guards(T) methods of ModelExt . Requires impl_ext . |
bool |
false |
Field Attributes
Values can be customized with the entry
attribute. Each field must be specified
as either key
or value
with the position
argument. Note that composite
variables (multiple key
or value
fields) are combined as tuples in the order
they are defined in the struct.
Argument | Description | Type | Default |
---|---|---|---|
position |
The position of the field in an entry, either a key or a value . |
String |
N/A |
Implementation details
General notes regarding trait and type generation.
String
Table Definitions
redb_model
will replace String
with &str
for table definitions. This
is so that composite (tuple) variables can be borrowed and passed to database
handlers without destructuring the DTO.
Unit type values
The unit type ()
must be passed if no value is defined.
#[derive(Model)]
#[model(name = "outbound_edge", impl_ext)]
struct Edge {
#[entry(position(key))]
source: [u8; 16],
#[entry(position(key))]
target: [u8; 16],
}
let k = ([0; 16], [1; 16]);
let v = ();
let e = Edge::from_values((k, v));
License: MIT OR Apache-2.0
lib.rs
:
Derive macro for the redb_model
crate.
Dependencies
~1.3–1.8MB
~42K SLoC