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use super::{DescribedQuery, ExternalConnector, IsolationLevel, ResultSet, Transaction};
use crate::ast::*;
use async_trait::async_trait;
pub trait GetRow {
fn get_result_row(&self) -> crate::Result<Vec<Value<'static>>>;
}
pub trait TakeRow {
fn take_result_row(&mut self) -> crate::Result<Vec<Value<'static>>>;
}
pub trait ToColumnNames {
fn to_column_names(&self) -> Vec<String>;
}
/// Represents a connection or a transaction that can be queried.
#[async_trait]
pub trait Queryable: Send + Sync {
/// Returns a reference to self as an ExternalConnector if available.
fn as_external_connector(&self) -> Option<&dyn ExternalConnector> {
None
}
/// Execute the given query.
async fn query(&self, q: Query<'_>) -> crate::Result<ResultSet>;
/// Execute a query given as SQL, interpolating the given parameters.
async fn query_raw(&self, sql: &str, params: &[Value<'_>]) -> crate::Result<ResultSet>;
/// Execute a query given as SQL, interpolating the given parameters.
///
/// On Postgres, query parameters types will be inferred from the values
/// instead of letting Postgres infer them based on their usage in the SQL query.
///
/// NOTE: This method will eventually be removed & merged into Queryable::query_raw().
async fn query_raw_typed(&self, sql: &str, params: &[Value<'_>]) -> crate::Result<ResultSet>;
/// Execute the given query, returning the number of affected rows.
async fn execute(&self, q: Query<'_>) -> crate::Result<u64>;
/// Execute a query given as SQL, interpolating the given parameters and
/// returning the number of affected rows.
async fn execute_raw(&self, sql: &str, params: &[Value<'_>]) -> crate::Result<u64>;
/// Execute a query given as SQL, interpolating the given parameters and
/// returning the number of affected rows.
///
/// On Postgres, query parameters types will be inferred from the values
/// instead of letting Postgres infer them based on their usage in the SQL query.
///
/// NOTE: This method will eventually be removed & merged into Queryable::query_raw().
async fn execute_raw_typed(&self, sql: &str, params: &[Value<'_>]) -> crate::Result<u64>;
/// Run a command in the database, for queries that can't be run using
/// prepared statements.
async fn raw_cmd(&self, cmd: &str) -> crate::Result<()>;
/// Return the version of the underlying database, queried directly from the
/// source. This corresponds to the `version()` function on PostgreSQL for
/// example. The version string is returned directly without any form of
/// parsing or normalization.
async fn version(&self) -> crate::Result<Option<String>>;
/// Prepares a statement and returns type information.
async fn describe_query(&self, sql: &str) -> crate::Result<DescribedQuery>;
/// Returns false, if connection is considered to not be in a working state.
fn is_healthy(&self) -> bool;
/// Execute a `SELECT` query.
async fn select(&self, q: Select<'_>) -> crate::Result<ResultSet> {
self.query(q.into()).await
}
/// Execute an `INSERT` query.
async fn insert(&self, q: Insert<'_>) -> crate::Result<ResultSet> {
self.query(q.into()).await
}
/// Execute an `UPDATE` query, returning the number of affected rows.
async fn update(&self, q: Update<'_>) -> crate::Result<u64> {
self.execute(q.into()).await
}
/// Execute a `DELETE` query.
async fn delete(&self, q: Delete<'_>) -> crate::Result<()> {
self.query(q.into()).await?;
Ok(())
}
/// Execute an arbitrary function in the beginning of each transaction.
async fn server_reset_query(&self, _: &dyn Transaction) -> crate::Result<()> {
Ok(())
}
/// Statement to begin a transaction
fn begin_statement(&self) -> &'static str {
"BEGIN"
}
/// Sets the transaction isolation level to given value.
/// Implementers have to make sure that the passed isolation level is valid for the underlying database.
async fn set_tx_isolation_level(&self, isolation_level: IsolationLevel) -> crate::Result<()>;
/// Signals if the isolation level SET needs to happen before or after the tx BEGIN.
fn requires_isolation_first(&self) -> bool;
}
/// A thing that can start a new transaction.
#[async_trait]
pub trait TransactionCapable: Queryable {
/// Starts a new transaction
async fn start_transaction<'a>(
&'a self,
isolation: Option<IsolationLevel>,
) -> crate::Result<Box<dyn Transaction + 'a>>;
}
#[cfg(any(
feature = "sqlite-native",
feature = "mssql-native",
feature = "postgresql-native",
feature = "mysql-native"
))]
macro_rules! impl_default_TransactionCapable {
($t:ty) => {
#[async_trait]
impl TransactionCapable for $t {
async fn start_transaction<'a>(
&'a self,
isolation: Option<IsolationLevel>,
) -> crate::Result<Box<dyn crate::connector::Transaction + 'a>> {
let opts = crate::connector::TransactionOptions::new(isolation, self.requires_isolation_first());
Ok(Box::new(
crate::connector::DefaultTransaction::new(self, self.begin_statement(), opts).await?,
))
}
}
};
}
#[cfg(any(
feature = "sqlite-native",
feature = "mssql-native",
feature = "postgresql-native",
feature = "mysql-native"
))]
pub(crate) use impl_default_TransactionCapable;