//! Types for returning SQL type information about queries.

use std::fmt::{self, Debug};

use crate::database::Database;

/// The return type of [Executor::describe].

#[non_exhaustive]

pub struct Describe<DB>

where

DB: Database + ?Sized,

{

/// The expected types for the parameters of the query.

pub param_types: Box<[DB::TypeInfo]>,

/// The type and table information, if any for the results of the query.

pub result_columns: Box<[Column<DB>]>,

}

impl<DB> Debug for Describe<DB>

where

DB: Database,

DB::TypeInfo: Debug,

Column<DB>: Debug,

{

fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

f.debug_struct("Describe")

.field("param_types", &self.param_types)

.field("result_columns", &self.result_columns)

.finish()

}

}

/// A single column of a result set.

#[non_exhaustive]

pub struct Column<DB>

where

DB: Database + ?Sized,

{

pub name: Option<Box<str>>,

pub table_id: Option<DB::TableId>,

pub type_info: DB::TypeInfo,

/// Whether or not the column cannot be `NULL` (or if that is even knowable).

pub non_null: Option<bool>,

}

impl<DB> Debug for Column<DB>

where

DB: Database + ?Sized,

DB::TableId: Debug,

DB::TypeInfo: Debug,

{

fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {

f.debug_struct("Column")

.field("name", &self.name)

.field("table_id", &self.table_id)

.field("type_id", &self.type_info)

.field("nonnull", &self.non_null)

.finish()

}

}