QueryTrait

risingwave_meta_model_migration::sea_orm

Trait QueryTrait 

pub trait QueryTrait {
    type QueryStatement: QueryStatementBuilder;

    // Required methods
    fn query(&mut self) -> &mut Self::QueryStatement;
    fn as_query(&self) -> &Self::QueryStatement;
    fn into_query(self) -> Self::QueryStatement;

    // Provided methods
    fn build(&self, db_backend: DatabaseBackend) -> Statement { ... }
    fn apply_if<T, F>(self, val: Option<T>, if_some: F) -> Self
       where Self: Sized,
             F: FnOnce(Self, T) -> Self { ... }
}
Expand description

A Trait for any type performing queries on a Model or ActiveModel

Required Associated Types§

type QueryStatement: QueryStatementBuilder

Constrain the QueryStatement to QueryStatementBuilder trait

Required Methods§

fn query(&mut self) -> &mut Self::QueryStatement

Get a mutable ref to the query builder

fn as_query(&self) -> &Self::QueryStatement

Get an immutable ref to the query builder

fn into_query(self) -> Self::QueryStatement

Take ownership of the query builder

Provided Methods§

fn build(&self, db_backend: DatabaseBackend) -> Statement

Build the query as Statement

fn apply_if<T, F>(self, val: Option<T>, if_some: F) -> Self
where Self: Sized, F: FnOnce(Self, T) -> Self,

Apply an operation on the QueryTrait::QueryStatement if the given Option<T> is Some(_)

§Example
use sea_orm::{entity::*, query::*, tests_cfg::cake, DbBackend};

assert_eq!(
    cake::Entity::find()
        .apply_if(Some(3), |mut query, v| {
            query.filter(cake::Column::Id.eq(v))
        })
        .apply_if(Some(100), QuerySelect::limit)
        .apply_if(None, QuerySelect::offset::<Option<u64>>) // no-op
        .build(DbBackend::Postgres)
        .to_string(),
    r#"SELECT "cake"."id", "cake"."name" FROM "cake" WHERE "cake"."id" = 3 LIMIT 100"#
);

Implementors§