Struct polodb_core::db::Collection

pub struct Collection<'a> { /* fields omitted */ }

A wrapper of collection in struct.

All CURD methods can be done through this structure.

Find/Update/Delete operations need a query object.

Query operation:

Name	Description
$eq	Matches values that are equal to a specified value.
$gt	Matches values that are greater than a specified value.
$gte	Matches values that are greater than or equal to a specified value.
$in	Matches any of the values specified in an array.
$lt	Matches values that are less than a specified value.
$lte	Matches values that are less than or equal to a specified value.
$ne	Matches all values that are not equal to a specified value.
$nin	Matches none of the values specified in an array.

Logical operation:

Name	Description
$and	Joins query clauses with a logical AND returns all documents that match the conditions of both clauses.
$or	Joins query clauses with a logical OR returns all documents that match the conditions of either clause.

Example:

use std::rc::Rc;
use polodb_core::Database;
use polodb_bson::doc;

let mut db = Database::open_file("/tmp/test-collection").unwrap();
let mut collection = db.collection("test").unwrap();
collection.insert(doc! {
    "_id": 0,
    "name": "Vincent Chan",
    "score": 99.99,
}.as_mut());

Implementations

impl<'a> Collection<'a>

pub fn find_all(&mut self) -> DbResult<Vec<Rc<Document>>>

all the data in the collection return.

pub fn find(&mut self, query: &Document) -> DbResult<Vec<Rc<Document>>>

When query document is passed to the function. The result satisfies the query document.

pub fn find_one(&mut self, query: &Document) -> DbResult<Option<Rc<Document>>>

Return the first element in the collection satisfies the query.

pub fn name(&self) -> &str

pub fn count(&mut self) -> DbResult<u64>

Return the size of all data in the collection.

pub fn update(
    &mut self,
    query: Option<&Document>,
    update: &Document
) -> DbResult<usize>

When query is None, all the data in the collection will be updated. Basically the same as MongoDB.

Field Update Operators:

Name	Description
$inc	Increments the value of the field by the specified amount.
$min	Only updates the field if the specified value is less than the existing field value.
$max	Only updates the field if the specified value is greater than the existing field value.
$mul	Multiplies the value of the field by the specified amount.
$rename	Renames a field.
$set	Sets the value of a field in a document.
$unset	Removes the specified field from a document.

pub fn insert(&mut self, doc: &mut Document) -> DbResult<bool>

Insert a document into the database. The returning boolean value represents if the DB inserted a “_id” for you.

pub fn delete(&mut self, query: Option<&Document>) -> DbResult<usize>

When query is None, all the data in the collection will be deleted.

The size of data deleted returns.