Trait RelayDatabaseAdapter 

pub trait RelayDatabaseAdapter: DatabaseAdapter {
    // Required method
    fn execute_relay_page<'a>(
        &'a self,
        view: &'a str,
        cursor_column: &'a str,
        after: Option<CursorValue>,
        before: Option<CursorValue>,
        limit: u32,
        forward: bool,
        where_clause: Option<&'a WhereClause>,
        order_by: Option<&'a [OrderByClause]>,
        include_total_count: bool,
    ) -> impl Future<Output = Result<RelayPageResult>> + Send + 'a;

    // Provided method
    fn execute_relay_page_with_session<'a>(
        &'a self,
        view: &'a str,
        cursor_column: &'a str,
        after: Option<CursorValue>,
        before: Option<CursorValue>,
        limit: u32,
        forward: bool,
        where_clause: Option<&'a WhereClause>,
        order_by: Option<&'a [OrderByClause]>,
        include_total_count: bool,
        _session_vars: &'a [(&'a str, &'a str)],
    ) -> impl Future<Output = Result<RelayPageResult>> + Send + 'a { ... }
}

Database adapter supertrait for adapters that implement Relay cursor pagination.

Only adapters that genuinely support keyset pagination need to implement this trait. Non-implementing adapters carry no relay code at all — no stubs, no flags.

Implementors

• PostgresAdapter — full keyset pagination
• MySqlAdapter — keyset pagination with ? params
• CachedDatabaseAdapter<A> — delegates to inner A

Usage

Construct an Executor with Executor::new_with_relay to enable relay query execution. The bound A: RelayDatabaseAdapter is enforced at that call site.

Required Methods

fn execute_relay_page<'a>( &'a self, view: &'a str, cursor_column: &'a str, after: Option<CursorValue>, before: Option<CursorValue>, limit: u32, forward: bool, where_clause: Option<&'a WhereClause>, order_by: Option<&'a [OrderByClause]>, include_total_count: bool, ) -> impl Future<Output = Result<RelayPageResult>> + Send + 'a

Execute keyset (cursor-based) pagination against a JSONB view.

Arguments

• view — SQL view name (will be quoted before use)
• cursor_column — column used as the pagination key (e.g. pk_user, id)
• after — forward cursor: return rows where cursor_column > after
• before — backward cursor: return rows where cursor_column < before
• limit — row fetch count (pass page_size + 1 to detect hasNextPage)
• forward — true → ASC order; false → DESC (re-sorted ASC via subquery)
• where_clause — optional user-supplied filter applied after the cursor condition
• order_by — optional custom sort; cursor column appended as tiebreaker
• include_total_count — when true, compute the matching row count before LIMIT

Errors

Returns FraiseQLError::Database on SQL execution failure.

Provided Methods

fn execute_relay_page_with_session<'a>( &'a self, view: &'a str, cursor_column: &'a str, after: Option<CursorValue>, before: Option<CursorValue>, limit: u32, forward: bool, where_clause: Option<&'a WhereClause>, order_by: Option<&'a [OrderByClause]>, include_total_count: bool, _session_vars: &'a [(&'a str, &'a str)], ) -> impl Future<Output = Result<RelayPageResult>> + Send + 'a

Connection-affine variant of execute_relay_page.

Applies session_vars transaction-locally on the same connection that runs the page (and total-count) queries, so RLS-protected relay pagination over views reading current_setting() returns the correct tenant’s rows (fixes #329 for the cursor-pagination path).

Adapters that do not support session variables inherit the default, which drops session_vars and delegates to execute_relay_page.

Errors

Same errors as execute_relay_page; additionally returns FraiseQLError::Database if set_config fails.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl RelayDatabaseAdapter for PostgresAdapter