Connection

To access Postgresql, tokio-postgres to be used. You can also use deadpool-postgres.

Code generation

define_ar is used to generate the code.

``` rust use arysn::generator::config::{BelongsToConfig, Config, HasManyConfig}; use arysn::generator::define_ar;

fn main() { definear(vec![ Config { path: "src/generated/user.rs", tablename: "users", structname: "User", hasmany: vec![ HasManyConfig { field: "roles", structname: "Role", foreignkey: "userid", }, ], hasone: vec![], belongsto: vec![], }, Config { path: "src/generated/role.rs", tablename: "roles", structname: "Role", hasmany: vec![], hasone: vec![], belongsto: vec![BelongsToConfig { field: "user", structname: "User", foreignkey: "user_id", } } ]).unwrap(); ```

The following four files will be generated.

user.rs
user_impl.rs
role.rs
role_impl.rs
enums.rs

user.rs and role.rs are intended to be used in frontend applications such as Yew. userimpl.rs and roleimpl.rs contain DB access code. enums.rs is generated by CREATE TYPE SQL.

Query

``` rust let conn = ... // tokio-postgres or deadpool-postgres client let users: Vec = User::select().active().eq(true).load(&conn).await?;

let user: User = User::select().id(1).first(&conn).await?;

use arysn::Optional; let user: Option = User::select().id(1).first(&conn).await.optional()?; ```

Join

rust let users: Vec<User> = User::select().roles(|role| role.role_type().eq(RoleType::Admin)) .load(&conn).await?;

N+1

rust let users: Vec<User> = User::select().roles(|role| role.preload()) .load(&conn).await?;

SQL looks like this

sql SELECT * FORM users; SELECT * FROM rolse WERE WHERE id IN (....);

The conditions before the preload are used to join.

rust let users: Vec<User> = User::select() .roles(|role| role.role_type().eq(RoleType::Admin).preload()) .load(&conn).await?;

SQL looks like this

sql SELECT * FORM users INNER JOIN roles ON roles.user_id=users.id WHERE roles.role_types='admin'; SELECT * FROM rolse WERE WHERE role_types='admin' id IN (....);

Conditions after the preload are not used when joining.

rust let users: Vec<User> = User::select() .roles(|role| role.preload().role_type().eq(RoleType::Admin)) .load(&conn).await?;

SQL looks like this

sql SELECT * FORM users; SELECT * FROM rolse WERE WHERE role_types='admin' id IN (....);

UUID

To use the UUID, you need to specify features for tokio-postgres and uuid.

Cargo.toml

toml [dependencies] tokio-postgres = { version = "0.7", features = ["with-chrono-0_4", "with-uuid-0_8"] } uuid = { version = "0.8", features = ["serde"] }

PostGIS

Only PostGIS POINT is supported. You must specify gis featuers.

Cargo.toml

toml [dependencies] arysn = { version = "0.3", features = ["gis"] }