Trait Statement

pub trait Statement<'q>: Send + Sync {
    type Database: Database;

    // Required methods
    fn to_owned(&self) -> <Self::Database as Database>::Statement<'static>;
    fn sql(&self) -> &str;
    fn parameters(
        &self,
    ) -> Option<Either<&[<Self::Database as Database>::TypeInfo], usize>>;
    fn columns(&self) -> &[<Self::Database as Database>::Column];
    fn query(
        &self,
    ) -> Query<'_, Self::Database, <Self::Database as Database>::Arguments<'_>>;
    fn query_with<'s, A>(&'s self, arguments: A) -> Query<'s, Self::Database, A>
       where A: IntoArguments<'s, Self::Database>;
    fn query_as<O>(
        &self,
    ) -> QueryAs<'_, Self::Database, O, <Self::Database as Database>::Arguments<'_>>
       where O: for<'r> FromRow<'r, <Self::Database as Database>::Row>;
    fn query_as_with<'s, O, A>(
        &'s self,
        arguments: A,
    ) -> QueryAs<'s, Self::Database, O, A>
       where O: for<'r> FromRow<'r, <Self::Database as Database>::Row>,
             A: IntoArguments<'s, Self::Database>;
    fn query_scalar<O>(
        &self,
    ) -> QueryScalar<'_, Self::Database, O, <Self::Database as Database>::Arguments<'_>>
       where (O,): for<'r> FromRow<'r, <Self::Database as Database>::Row>;
    fn query_scalar_with<'s, O, A>(
        &'s self,
        arguments: A,
    ) -> QueryScalar<'s, Self::Database, O, A>
       where (O,): for<'r> FromRow<'r, <Self::Database as Database>::Row>,
             A: IntoArguments<'s, Self::Database>;

    // Provided methods
    fn column<I>(&self, index: I) -> &<Self::Database as Database>::Column
       where I: ColumnIndex<Self> { ... }
    fn try_column<I>(
        &self,
        index: I,
    ) -> Result<&<Self::Database as Database>::Column, Error>
       where I: ColumnIndex<Self> { ... }
}

An explicitly prepared statement.

Statements are prepared and cached by default, per connection. This type allows you to look at that cache in-between the statement being prepared and it being executed. This contains the expected columns to be returned and the expected parameter types (if available).

Statements can be re-used with any connection and on first-use it will be re-prepared and cached within the connection.

Required Associated Types

type Database: Database

Required Methods

fn to_owned(&self) -> <Self::Database as Database>::Statement<'static>

Creates an owned statement from this statement reference. This copies the original SQL text.

fn sql(&self) -> &str

Get the original SQL text used to create this statement.

fn parameters( &self, ) -> Option<Either<&[<Self::Database as Database>::TypeInfo], usize>>

Get the expected parameters for this statement.

The information returned depends on what is available from the driver. SQLite can only tell us the number of parameters. PostgreSQL can give us full type information.

fn columns(&self) -> &[<Self::Database as Database>::Column]

Get the columns expected to be returned by executing this statement.

fn query( &self, ) -> Query<'_, Self::Database, <Self::Database as Database>::Arguments<'_>>

fn query_with<'s, A>(&'s self, arguments: A) -> Query<'s, Self::Database, A>

where A: IntoArguments<'s, Self::Database>,

fn query_as<O>( &self, ) -> QueryAs<'_, Self::Database, O, <Self::Database as Database>::Arguments<'_>>

where O: for<'r> FromRow<'r, <Self::Database as Database>::Row>,

fn query_as_with<'s, O, A>( &'s self, arguments: A, ) -> QueryAs<'s, Self::Database, O, A>

where O: for<'r> FromRow<'r, <Self::Database as Database>::Row>, A: IntoArguments<'s, Self::Database>,

fn query_scalar<O>( &self, ) -> QueryScalar<'_, Self::Database, O, <Self::Database as Database>::Arguments<'_>>

where (O,): for<'r> FromRow<'r, <Self::Database as Database>::Row>,

fn query_scalar_with<'s, O, A>( &'s self, arguments: A, ) -> QueryScalar<'s, Self::Database, O, A>

where (O,): for<'r> FromRow<'r, <Self::Database as Database>::Row>, A: IntoArguments<'s, Self::Database>,

Provided Methods

fn column<I>(&self, index: I) -> &<Self::Database as Database>::Column

where I: ColumnIndex<Self>,

Gets the column information at index.

A string index can be used to access a column by name and a usize index can be used to access a column by position.

Panics

Panics if index is out of bounds. See try_column for a non-panicking version.

fn try_column<I>( &self, index: I, ) -> Result<&<Self::Database as Database>::Column, Error>

where I: ColumnIndex<Self>,

Gets the column information at index or a ColumnIndexOutOfBounds error if out of bounds.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<'q> Statement<'q> for SqliteStatement<'q>

type Database = Sqlite