A SQLite database adapter for ElizaOS that provides persistent storage capabilities with vector similarity search support. This adapter implements the IDatabaseAdapter interface and extends the DatabaseAdapter base class to provide a lightweight, file-based storage solution ideal for development and embedded environments.

• Full SQLite database implementation of ElizaOS database interface
• Vector similarity search via sqlite-vec extension
• JSON validation and foreign key constraints
• Built-in caching system
• Comprehensive transaction support with circuit breaker pattern
• Support for storing and retrieving:
  • Memory entries with embeddings
  • User accounts and relationships
  • Goals and objectives
  • Room and participant management
  • Knowledge base with RAG support
  • System logs and cache

npm install @elizaos-plugins/adapter-sqlite

• better-sqlite3 (v11.8.1)
• sqlite-vec (v0.1.6)
• whatwg-url (v7.1.0)

import sqlitePlugin from '@elizaos-plugins/adapter-sqlite';
import { IAgentRuntime } from '@elizaos/core';

// Initialize with ElizaOS runtime
function initializeAgent(runtime: IAgentRuntime) {
    runtime.use(sqlitePlugin);
}

// Or initialize directly
import Database from 'better-sqlite3';
import { SqliteDatabaseAdapter } from '@elizaos-plugins/adapter-sqlite';

const db = new Database('path/to/database.db');
const adapter = new SqliteDatabaseAdapter(db);
await adapter.init();

The adapter looks for the following configuration in your ElizaOS runtime:

• SQLITE_FILE: Path to the SQLite database file (default: ./data/db.sqlite)

By default, the adapter creates a data directory in your project root and stores the database file there. Customize this by setting the SQLITE_FILE in your ElizaOS runtime configuration.

The adapter creates and manages these tables with appropriate indexes and constraints:

• accounts: User account information with JSON details
• memories: Memory entries with BLOB embeddings and JSON content
• goals: Task tracking with JSON objectives
• logs: System event logging
• participants: Room participation management
• relationships: User relationship tracking
• rooms: Conversation room management
• cache: Temporary data storage with JSON validation
• knowledge: RAG knowledge base with embedding support

Each table includes appropriate indexes and foreign key constraints. The complete schema is available in sqliteTables.ts.

The adapter implements vector similarity search using sqlite-vec for efficient embedding comparisons:

const memories = await adapter.searchMemories({
    tableName: "memories",
    roomId: "room-id",
    embedding: [/* vector */],
    match_threshold: 0.95,
    match_count: 10,
    unique: true
});

The adapter uses sqlite-vec to calculate L2 distances between embeddings stored as BLOB data. This enables efficient vector similarity searches for memory and knowledge retrieval.

This adapter is specifically designed for SQLite and implements ElizaOS's IDatabaseAdapter interface. For other databases, use the appropriate adapter (MongoDB, PostgreSQL, etc.).

Embeddings are stored as BLOB data in SQLite using Float32Array, with automatic conversion between formats as needed.

Yes, the adapter implements the framework's circuit breaker pattern and transaction support through better-sqlite3.

The adapter provides a built-in caching system through the cache table with support for JSON validation and automatic timestamp management.

While the adapter is built on production-ready better-sqlite3, it's primarily designed for development and embedded environments. For production deployments, consider PostgreSQL or MongoDB adapters.

Use standard SQLite backup procedures - either file system backup of the .sqlite file when the database is not in use, or SQLite's online backup API.

The adapter supports any embedding dimension through BLOB storage, though the default configuration is optimized for 384-dimensional vectors commonly used by local models.