Trait Source 

pub trait Source {
    // Required methods
    fn open(
        &mut self,
        connection: &Map<String, Value>,
        read_only: bool,
    ) -> Result<()>;
    fn execute(
        &mut self,
        sql: &str,
        row_limit: Option<u64>,
        out: &mut dyn ResultSink,
    ) -> Result<()>;

    // Provided methods
    fn connection_fields(&self) -> Vec<ConnectionField> { ... }
    fn identifier_quote(&self) -> Option<&'static str> { ... }
    fn string_literal(&self) -> Option<&'static str> { ... }
    fn single_writer(&self) -> Option<SingleWriter> { ... }
    fn validate_connection(
        &self,
        _connection: &Map<String, Value>,
    ) -> Vec<String> { ... }
    fn open_sandboxed(&mut self, connection: &Map<String, Value>) -> Result<()> { ... }
    fn check(&mut self, _sql: &str) -> Result<()> { ... }
    fn load(&mut self, _name: &str, _data: &mut ResultSet<'_>) -> Result<Loaded> { ... }
    fn catalog(
        &mut self,
        _tables: &[String],
        _schemas: &[String],
    ) -> Result<Value> { ... }
    fn close(&mut self) { ... }
}

Required Methods

fn open( &mut self, connection: &Map<String, Value>, read_only: bool, ) -> Result<()>

fn execute( &mut self, sql: &str, row_limit: Option<u64>, out: &mut dyn ResultSink, ) -> Result<()>

Run one statement. row_limit is a hint; the SDK enforces it either way.

Provided Methods

fn connection_fields(&self) -> Vec<ConnectionField>

fn identifier_quote(&self) -> Option<&'static str>

The character the database quotes identifiers with, reported in describe: " for most SQL databases, a backtick for Databricks and MySQL. Core doubles it inside a name.

fn string_literal(&self) -> Option<&'static str>

How core should spell a string holding ' or \ (an inlined lookup), reported in describe: None for chr(39)/chr(92), Some("backslash") for a database without chr().

fn single_writer(&self) -> Option<SingleWriter>

A connection field naming a file only one process may write at a time, reported in describe (DuckDB’s path, unless :memory:): core then runs one Binding at a time on a connection that sets it.

fn validate_connection(&self, _connection: &Map<String, Value>) -> Vec<String>

Rules the declared Source::connection_fields can’t express (two keys that can’t go together, a value’s form), each a sentence naming the field, never its value. Static: no network. Run by validate_connection and before open. A value set through an unset env_var() arrives as null.

fn open_sandboxed(&mut self, connection: &Map<String, Value>) -> Result<()>

Open a read-only session for core’s dre query: also refuse files, programs and the network outside the database where the engine can. Default: a read-only Source::open.

fn check(&mut self, _sql: &str) -> Result<()>

Verify without executing. Only called when the plugin advertises check.

fn load(&mut self, _name: &str, _data: &mut ResultSet<'_>) -> Result<Loaded>

Load data into a temporary table on the session, named after name. Only called when the plugin advertises load.

fn catalog(&mut self, _tables: &[String], _schemas: &[String]) -> Result<Value>

Discover accessible relations through native metadata. Only called when the plugin advertises catalog; both lists use the existing dre catalog request.

fn close(&mut self)

End the session cleanly (called on close and at end of input, before exiting).

Dyn Compatibility

This trait is dyn compatible.

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

Implementors