Struct native_db::transaction::query::RLen

pub struct RLen<'db, 'txn> { /* private fields */ }

Get the number of values in the database.

Implementations

impl RLen<'_, '_>

pub fn primary<T: Input>(&self) -> Result<u64>

Get the number of values.

Example

use native_db::*;
use native_model::{native_model, Model};
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize)]
#[native_model(id=1, version=1)]
#[native_db]
struct Data {
    #[primary_key]
    id: u64,
}

fn main() -> Result<(), db_type::Error> {
    let mut builder = DatabaseBuilder::new();
    builder.define::<Data>()?;
    let db = builder.create_in_memory()?;
     
    // Open a read transaction
    let r = db.r_transaction()?;
     
    // Get all values
    let _number:u64 = r.len().primary::<Data>()?;
    Ok(())
}

pub fn secondary<T: Input>( &self, _key_def: impl KeyDefinition<DatabaseSecondaryKeyOptions> ) -> Result<Option<T>>

TODO: needs to be implemented

Get the number of values by secondary key.

Anatomy of a secondary key it is a enum with the following structure: <table_name>Key::<name>.

If the secondary key is optional you will get all values that have the secondary key set.