Struct native_db::transaction::query::SecondaryScan

pub struct SecondaryScan<PrimaryTable, SecondaryTable, T: Input>
where
    PrimaryTable: ReadableTable<DatabaseInnerKeyValue, &'static [u8]>,
    SecondaryTable: ReadableTable<DatabaseInnerKeyValue, DatabaseInnerKeyValue>,
{ /* private fields */ }

Scan values from the database by secondary key.

Implementations

impl<PrimaryTable, SecondaryTable, T: Input> SecondaryScan<PrimaryTable, SecondaryTable, T>

where PrimaryTable: ReadableTable<DatabaseInnerKeyValue, &'static [u8]>, SecondaryTable: ReadableTable<DatabaseInnerKeyValue, DatabaseInnerKeyValue>,

pub fn all(&self) -> SecondaryScanIterator<'_, PrimaryTable, T>

Iterate over all values by secondary key.

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

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

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,
    #[secondary_key(optional)]
    name: Option<String>,
}

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 only values that have the secondary key set (name is not None)
    let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.all().collect();
    Ok(())
}

pub fn range<TR: InnerKeyValue, R: RangeBounds<TR>>( &self, range: R ) -> SecondaryScanIterator<'_, PrimaryTable, T>

Iterate over all values by secondary key.

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

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,
    #[secondary_key]
    name: String,
}

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 only values that have the secondary key name from C to the end
    let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.range("C"..).collect();
    Ok(())
}

pub fn start_with<'a>( &'a self, start_with: impl InnerKeyValue + 'a ) -> SecondaryScanIteratorStartWith<'a, PrimaryTable, T>

Iterate over all values by secondary key.

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

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,
    #[secondary_key]
    name: String,
}

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 only values that have the secondary key name starting with "hello"
    let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.start_with("hello").collect();
    Ok(())
}