Struct Db 

pub struct Db { /* private fields */ }

The main database handle for NervusDB v2.

Example

use nervusdb_v2::Db;

let db = Db::open("my_graph.ndb").unwrap();

Concurrency

Db can be shared across threads. Internal mutations are serialized through a single writer lock.

Implementations

impl Db

pub fn open(path: impl AsRef<Path>) -> Result<Self>

Opens a database at the given path.

The path can be:

• A directory path: files will be created as <path>.ndb and <path>.wal
• An explicit .ndb or .wal path: the other file is inferred

Returns an error if the database cannot be opened.

pub fn open_paths( ndb_path: impl AsRef<Path>, wal_path: impl AsRef<Path>, ) -> Result<Self>

Opens a database with explicit paths for the data and WAL files.

Example

let db = Db::open_paths("graph.ndb", "graph.wal").unwrap();

pub fn ndb_path(&self) -> &Path

Returns the path to the main data file (.ndb).

pub fn wal_path(&self) -> &Path

Returns the path to the WAL file (.wal).

pub fn begin_read(&self) -> ReadTxn

Begins a read-only transaction.

The returned ReadTxn provides a consistent view of the database at the time of creation. It can be used concurrently with other read transactions and will not see writes that commit after its creation.

pub fn snapshot(&self) -> DbSnapshot

Creates a snapshot for query execution.

Returns a DbSnapshot that implements GraphSnapshot trait, suitable for use with the query engine.

pub fn begin_write(&self) -> WriteTxn<'_>

Begins a write transaction.

Write transactions are exclusive - only one can exist at a time. The transaction must be explicitly committed with commit().

Panics

Panics if another write transaction is already in progress.

pub fn compact(&self) -> Result<()>

Triggers a compaction operation.

Compaction merges frozen MemTables into CSR segments and removes tombstoned entries. This is a potentially expensive operation that should be done during maintenance windows.

pub fn checkpoint(&self) -> Result<()>

Creates a durability checkpoint.

In MVP, this is equivalent to compact(). Future versions may implement lightweight checkpoints that don’t require full compaction.

pub fn close(self) -> Result<()>

Explicitly closes the DB and performs a best-effort checkpoint-on-close (T106).

This is intentionally not implemented in Drop to avoid hiding expensive IO.

pub fn create_index(&self, label: &str, property: &str) -> Result<()>

Creates an index on the specified label and property.

Example

db.create_index("User", "email")?;

Trait Implementations

impl Debug for Db

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.