Struct BackendClient 

pub struct BackendClient {
    pub server_parameters: HashMap<String, String>,
    pub backend_pid: Option<u32>,
    pub backend_secret: Option<u32>,
    /* private fields */
}

An established, authenticated client connection to a backend.

Fields

server_parameters: HashMap<String, String>

Parameter values the server sent during startup (client_encoding, server_version, TimeZone, …). Useful for diagnostics.

backend_pid: Option<u32>

BackendKeyData cached for potential cancel requests.

backend_secret: Option<u32>

Implementations

impl BackendClient

pub async fn connect(cfg: &BackendConfig) -> BackendResult<Self>

Connect, TLS-negotiate, authenticate, and drain server-initialisation frames through ReadyForQuery. On success the client is idle and ready to run SQL.

pub async fn simple_query(&mut self, sql: &str) -> BackendResult<QueryResult>

Run a simple-query (SQL text) and collect every resulting row into a QueryResult. For statements that don’t return rows (DDL, SET, etc.) rows will be empty and command_tag carries the completion string.

pub async fn query_with_params( &mut self, sql: &str, params: &[ParamValue], ) -> BackendResult<QueryResult>

Like simple_query but substitutes $1, $2, … with text-format literals before sending. We stick to simple-query rather than the extended protocol to keep the surface narrow.

pub async fn query_scalar(&mut self, sql: &str) -> BackendResult<TextValue>

Shorthand for a scalar lookup: runs sql, expects 1 column, 1 row.

pub async fn execute(&mut self, sql: &str) -> BackendResult<String>

Run a statement with no result set (DDL, SET, DO). Returns the command tag (e.g. "SET", "CREATE TABLE").

pub async fn copy_in( &mut self, copy_sql: &str, data: &[u8], ) -> BackendResult<u64>

Bulk-load rows via COPY <table> [(cols)] FROM STDIN (text format). data is the pre-encoded COPY text payload (rows already tab-delimited, escaped, and newline-terminated; no trailing \.). Returns the row count from the COPY n command tag.

On ANY failure the connection is drained back to ReadyForQuery, so a caller can fall back to per-row INSERTs cleanly — COPY is atomic, so a failed load leaves zero rows behind (no double-insert risk).

pub async fn close(self)

Close the connection gracefully (send Terminate, close socket).

pub fn is_tls(&self) -> bool

Report whether the underlying connection is over TLS.