Struct Connection 

pub struct Connection { /* private fields */ }

A connection to a KyuGraph database.

Connections share catalog and storage via Arc. Each query gets a consistent catalog snapshot for binding and planning; DDL mutates both catalog and storage atomically. Every query is wrapped in a transaction for crash safety and isolation.

Implementations

impl Connection

pub fn query(&self, cypher: &str) -> KyuResult<QueryResult>

Execute a Cypher statement, returning a QueryResult.

Each statement is wrapped in a transaction: read-only queries get a ReadOnly transaction, write queries get a Write transaction. The transaction is committed on success and rolled back on error.

pub fn query_with_params( &self, cypher: &str, params: HashMap<String, TypedValue>, ) -> KyuResult<QueryResult>

Execute a Cypher statement with parameter bindings for $param placeholders.

Parameters are resolved to literal values at bind time, before planning and execution. This is the preferred way to pass dynamic values safely.

use std::collections::HashMap;
use kyu_types::TypedValue;

let mut params = HashMap::new();
params.insert("min_age".to_string(), TypedValue::Int64(25));
let result = conn.query_with_params(
    "MATCH (p:Person) WHERE p.age > $min_age RETURN p.name",
    params,
).unwrap();

pub fn execute( &self, cypher: &str, params: HashMap<String, TypedValue>, env: HashMap<String, TypedValue>, ) -> KyuResult<QueryResult>

Full VM-style execution with both $param bindings and env() values.

The Cypher evaluator is treated like a virtual machine: it accepts a query string plus two context maps that are resolved before planning:

• params: $param placeholders → TypedValue
• env: env('KEY') lookups → TypedValue

use std::collections::HashMap;
use kyu_types::TypedValue;

let mut params = HashMap::new();
params.insert("name".to_string(), TypedValue::String("Alice".into()));
let mut env = HashMap::new();
env.insert("PREFIX".to_string(), TypedValue::String("graph_".into()));
let result = conn.execute(
    "MATCH (p:Person) WHERE p.name = $name RETURN p.name",
    params,
    env,
).unwrap();

pub fn apply_delta(&self, batch: DeltaBatch) -> KyuResult<DeltaStats>

Apply a batch of conflict-free, idempotent upserts that bypass OCC.

All deltas in the batch commit atomically via a single WAL append. Semantics are “last write wins” — safe only when upsert semantics are acceptable (ingestion pipelines, agentic code graphs, document processing).