feat(core): expand Executor with fetch_x, declare Column, Row, and QueryResult

sqlx-core/src/blocking/executor.rs

@@ -1,12 +1,14 @@
-use crate::Database;
-
 use super::Runtime;
+use crate::Database;
 
 pub trait Executor<Rt: Runtime>: crate::Executor<Rt>
 where
     Self::Database: Database<Rt>,
 {
-    fn execute<'x, 'e, 'q>(&'e mut self, sql: &'q str) -> crate::Result<()>
+    fn execute<'x, 'e, 'q>(
+        &'e mut self,
+        sql: &'q str,
+    ) -> crate::Result<<Self::Database as Database<Rt>>::QueryResult>
     where
         'e: 'x,
         'q: 'x;

sqlx-core/src/column.rs

@@ -0,0 +1,7 @@
+pub trait Column {
+    /// Returns the name or alias of the column.
+    fn name(&self) -> &str;
+
+    /// Returns the ordinal (also known as the index) of the column.
+    fn ordinal(&self) -> usize;
+}

sqlx-core/src/database.rs

@@ -1,6 +1,6 @@
 use std::fmt::Debug;
 
-use crate::{Connection, Runtime};
+use crate::{Column, Connection, QueryResult, Row, Runtime};
 
 /// A database driver.
 ///
@@ -13,6 +13,15 @@ where
 {
     /// The concrete [`Connection`] implementation for this database.
     type Connection: Connection<Rt, Database = Self> + ?Sized;
+
+    /// The concrete [`Column`] implementation for this database.
+    type Column: Column;
+
+    /// The concrete [`Row`] implementation for this database.
+    type Row: Row<Column = Self::Column>;
+
+    /// The concrete [`QueryResult`] implementation for this database.
+    type QueryResult: QueryResult;
 }
 
 /// Associates [`Database`] with a `Output` of a generic lifetime.

sqlx-core/src/executor.rs

@@ -11,13 +11,47 @@ use crate::{Database, Result, Runtime};
 /// A [`Connection`] is an `Executor` that guarantees that successive queries are ran on the
 /// same physical database connection.
 ///
+#[allow(clippy::type_complexity)]
 pub trait Executor<Rt: Runtime> {
     type Database: Database<Rt>;
 
     /// Execute the SQL query and return information about the result, including
     /// the number of rows affected, if any.
     #[cfg(feature = "async")]
-    fn execute<'x, 'e, 'q>(&'e mut self, sql: &'q str) -> BoxFuture<'x, Result<()>>
+    fn execute<'x, 'e, 'q>(
+        &'e mut self,
+        sql: &'q str,
+    ) -> BoxFuture<'x, Result<<Self::Database as Database<Rt>>::QueryResult>>
+    where
+        Rt: crate::Async,
+        'e: 'x,
+        'q: 'x;
+
+    #[cfg(feature = "async")]
+    fn fetch_all<'x, 'e, 'q>(
+        &'e mut self,
+        sql: &'q str,
+    ) -> BoxFuture<'x, Result<Vec<<Self::Database as Database<Rt>>::Row>>>
+    where
+        Rt: crate::Async,
+        'e: 'x,
+        'q: 'x;
+
+    #[cfg(feature = "async")]
+    fn fetch_optional<'x, 'e, 'q>(
+        &'e mut self,
+        sql: &'q str,
+    ) -> BoxFuture<'x, Result<Option<<Self::Database as Database<Rt>>::Row>>>
+    where
+        Rt: crate::Async,
+        'e: 'x,
+        'q: 'x;
+
+    #[cfg(feature = "async")]
+    fn fetch_one<'x, 'e, 'q>(
+        &'e mut self,
+        sql: &'q str,
+    ) -> BoxFuture<'x, Result<<Self::Database as Database<Rt>>::Row>>
     where
         Rt: crate::Async,
         'e: 'x,

sqlx-core/src/lib.rs

@@ -28,6 +28,10 @@ mod executor;
 mod options;
 mod pool;
 mod runtime;
+mod decode;
+mod row;
+mod query_result;
+mod column;
 
 #[doc(hidden)]
 pub mod io;
@@ -47,10 +51,13 @@ pub use acquire::Acquire;
 pub use blocking::runtime::Blocking;
 pub use close::Close;
 pub use connect::Connect;
+pub use column::Column;
 pub use connection::Connection;
 pub use database::{Database, HasOutput};
 pub use error::{DatabaseError, Error, Result};
 pub use executor::Executor;
+pub use query_result::QueryResult;
+pub use row::Row;
 pub use options::ConnectOptions;
 pub use pool::Pool;
 #[cfg(feature = "actix")]

sqlx-core/src/query_result.rs

@@ -0,0 +1,12 @@
+use std::fmt::Debug;
+
+/// Represents the execution result of an operation on the database server.
+///
+/// Returned from [`execute()`][crate::Executor::execute].
+///
+pub trait QueryResult: 'static + Sized + Debug + Extend<Self> {
+    /// Returns the number of rows changed, deleted, or inserted by the statement
+    /// if it was an `UPDATE`, `DELETE` or `INSERT`. For `SELECT` statements, returns
+    /// the number of rows returned.
+    fn rows_affected(&self) -> u64;
+}

sqlx-core/src/row.rs

@@ -0,0 +1,37 @@
+use crate::{Column, Database, Runtime};
+
+pub trait Row {
+    type Column: Column;
+
+    /// Returns `true` if the row contains only `NULL` values.
+    fn is_null(&self) -> bool;
+
+    /// Returns the number of columns in the row.
+    fn len(&self) -> usize;
+
+    /// Returns `true` if there are no columns in the row.
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Returns a reference to the columns in the row.
+    fn columns(&self) -> &[Self::Column];
+
+    /// Returns the column name, given the ordinal (also known as index) of the column.
+    fn column_name_of(&self, ordinal: usize) -> &str;
+
+    /// Returns the column name, given the ordinal (also known as index) of the column.
+    fn try_column_name_of(&self, ordinal: usize) -> crate::Result<&str>;
+
+    /// Returns the column ordinal, given the name of the column.
+    fn ordinal_of(&self, name: &str) -> usize;
+
+    /// Returns the column ordinal, given the name of the column.
+    fn try_ordinal_of(&self, name: &str) -> crate::Result<usize>;
+
+    fn try_get_raw(&self) -> crate::Result<&[u8]>;
+}
+
+// TODO: fn type_info_of(index)
+// TODO: fn try_type_info_of(index)
+// TODO: trait ColumnIndex

sqlx-core/src/runtime/async_std.rs

@@ -88,7 +88,7 @@ impl<'s> Stream<'s, AsyncStd> for TcpStream {
 
     #[doc(hidden)]
     fn shutdown_async(&'s mut self) -> Self::ShutdownFuture {
-        future::ready(TcpStream::shutdown(self, Shutdown::Both))
+        future::ready(Self::shutdown(self, Shutdown::Both))
     }
 
     #[doc(hidden)]
@@ -134,7 +134,7 @@ impl<'s> Stream<'s, AsyncStd> for UnixStream {
 
     #[doc(hidden)]
     fn shutdown_async(&'s mut self) -> Self::ShutdownFuture {
-        future::ready(UnixStream::shutdown(self, Shutdown::Both))
+        future::ready(Self::shutdown(self, Shutdown::Both))
     }
 
     #[doc(hidden)]