Struct Database

pub struct Database { /* private fields */ }

Available on crate feature db only.

A database connection structure that holds the connection to the database.

It is used to execute queries and interact with the database. The connection is established when the structure is created and closed when Self::close() is called.

Implementations

impl Database

pub async fn new<T: Into<String>>(url: T) -> Result<Self>

Creates a new database connection. The connection string should be in the format of the database URL.

Errors

This method can return an error if the connection to the database could not be established.

This method can return an error if the database URL is invalid.

Panics

This method will panic if the database URL is not supported.

Examples

use cot::db::Database;

#[tokio::main]
async fn main() {
    let db = Database::new("sqlite::memory:").await.unwrap();
}

pub async fn close(&self) -> Result<()>

Closes the database connection.

This method should be called when the database connection is no longer needed. The connection is closed and the resources are released.

Errors

This method can return an error if the connection to the database could not be closed gracefully, for instance because the connection has already been dropped.

Examples

use cot::db::Database;

#[tokio::main]
async fn main() {
    let db = Database::new("sqlite::memory:").await.unwrap();
    db.close().await.unwrap();
}

pub async fn insert<T: Model>(&self, data: &mut T) -> Result<()>

Inserts a new row into the database.

Errors

This method can return an error if the row could not be inserted into the database, for instance because the migrations haven’t been applied, or there was a problem with the database connection.

pub async fn insert_or_update<T: Model>(&self, data: &mut T) -> Result<()>

Inserts a new row into the database, or updates it if a row with the same primary key already exists.

Errors

This method can return an error if the row could not be inserted into the database, for instance because the migrations haven’t been applied, or there was a problem with the database connection.

pub async fn update<T: Model>(&self, data: &mut T) -> Result<()>

Updates an existing row in a database.

Errors

This method can return an error if the row could not be updated in the database, for instance because the migrations haven’t been applied, or there was a problem with the database connection.

This method can return an error if the row with the given primary key could not be found in the database.

pub async fn query<T: Model>(&self, query: &Query<T>) -> Result<Vec<T>>

Executes the given query and returns the results converted to the model type.

Errors

This method can return an error if the query is invalid.

This method can return an error if the data in the database is not compatible with the model (usually meaning the migrations haven’t been generated or applied).

Can return an error if the database connection is lost.

pub async fn get<T: Model>(&self, query: &Query<T>) -> Result<Option<T>>

Returns the first row that matches the given query. If no rows match the query, returns None.

Errors

This method can return an error if the query is invalid.

This method can return an error if the model doesn’t exist in the database (usually meaning the migrations haven’t been generated or applied).

Can return an error if the database connection is lost.

pub async fn exists<T: Model>(&self, query: &Query<T>) -> Result<bool>

Returns whether a row exists that matches the given query.

Errors

This method can return an error if the query is invalid.

This method can return an error if the model doesn’t exist in the database (usually meaning the migrations haven’t been generated or applied).

Can return an error if the database connection is lost.

pub async fn delete<T: Model>( &self, query: &Query<T>, ) -> Result<StatementResult>

Deletes all rows that match the given query.

Errors

This method can return an error if the query is invalid.

This method can return an error if the model doesn’t exist in the database (usually meaning the migrations haven’t been generated or applied).

Can return an error if the database connection is lost.

pub async fn raw(&self, query: &str) -> Result<StatementResult>

Executes a raw SQL query.

Errors

This method can return an error if the query is invalid.

Can return an error if the database connection is lost.

Examples

use cot::db::Database;

let db = Database::new("sqlite::memory:").await?;
db.raw("CREATE TABLE test (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT)")
    .await?;

pub async fn raw_with( &self, query: &str, values: &[&dyn ToDbValue], ) -> Result<StatementResult>

Executes a raw SQL query with parameters.

Errors

This method can return an error if the query is invalid.

Can return an error if the database connection is lost.

Examples

use cot::db::Database;

let db = Database::new("sqlite::memory:").await?;
db.raw("CREATE TABLE test (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT)")
    .await?;
db.raw_with("SELECT * FROM test WHERE id = ?", &[&1])
    .await?;

Trait Implementations

impl DatabaseBackend for Database

fn insert_or_update<'life0, 'life1, 'async_trait, T>( &'life0 self, data: &'life1 mut T, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Inserts a new row into the database, or updates an existing row if it already exists.

fn insert<'life0, 'life1, 'async_trait, T>( &'life0 self, data: &'life1 mut T, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Inserts a new row into the database.

fn update<'life0, 'life1, 'async_trait, T>( &'life0 self, data: &'life1 mut T, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Updates an existing row in the database.

fn query<'life0, 'life1, 'async_trait, T>( &'life0 self, query: &'life1 Query<T>, ) -> Pin<Box<dyn Future<Output = Result<Vec<T>>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Executes a query and returns the results converted to the model type.

fn get<'life0, 'life1, 'async_trait, T>( &'life0 self, query: &'life1 Query<T>, ) -> Pin<Box<dyn Future<Output = Result<Option<T>>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Returns the first row that matches the given query. If no rows match the query, returns None.

fn exists<'life0, 'life1, 'async_trait, T>( &'life0 self, query: &'life1 Query<T>, ) -> Pin<Box<dyn Future<Output = Result<bool>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Returns whether a row exists that matches the given query.

fn delete<'life0, 'life1, 'async_trait, T>( &'life0 self, query: &'life1 Query<T>, ) -> Pin<Box<dyn Future<Output = Result<StatementResult>> + Send + 'async_trait>>

where T: 'async_trait + Model, Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Deletes all rows that match the given query.

impl Debug for Database

fn fmt(&self, __derive_more_f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.