Dali 0.0.7-alpha

Dali - SurrealDB EF Core LINQ Provider

A complete example of building an EF Core–style LINQ provider for SurrealDB that transparently handles document, graph, and raw SQL query modes.

Architecture

Your LINQ Query
      │
      ▼
SurrealQueryable<T>          ← IQueryable<T> + IAsyncEnumerable<T>
      │
      ▼
SurrealQueryProvider          ← IQueryProvider — routing + async helpers
      │
      ▼
SurrealExpressionVisitor      ← Walks Expression tree → SurrealQL string
      │   ├── Document mode:  WHERE / ORDER BY / LIMIT / START
      │   ├── Graph mode:     ->edge->target traversal paths
      │   └── SQL mode:       raw SurrealQL pass-through
      ▼
TranslatedQuery               ← (SurrealQL string, QueryMode, ElementType)
      │
      ▼
SurrealHttpExecutor           ← POST /sql → parse [{ status, result }]
      │
      ▼
SurrealDB (HTTP API)

Query Modes

1. Document Mode

Standard LINQ → SurrealQL SELECT:

var adults = await ctx.People
    .Where(p => p.Age >= 18 && p.Name.Contains("A"))
    .OrderBy(p => p.Name)
    .Skip(20).Take(10)
    .ToListAsync();
// → SELECT * FROM person
//   WHERE (age >= 18) AND (string::contains(name, 'A'))
//   ORDER BY name ASC LIMIT 10 START 20

2. Graph Mode

Edge creation and traversal:

// RELATE
await ctx.Graph.RelateAsync<Knows>("person:alice", "person:bob",
    new Knows { Strength = 0.9 });
// → RELATE person:alice->knows->person:bob CONTENT {...}

// Traverse out
var friends = await ctx.Graph.TraverseOutAsync<Knows, Person>("person:alice");
// → SELECT ->knows->person.* FROM person:alice

// LINQ-style traverse
var result = await ctx.People
    .Where(p => p.Name == "Alice")
    .Traverse<Knows, Person>("out")
    .Where(p => p.Age > 18)
    .ToListAsync();
// → SELECT ->knows->person.* FROM person
//   WHERE name = 'Alice' AND age > 18

3. SQL / Analytic Mode

Full SurrealQL pass-through:

var stats = await ctx.QueryAsync<...>("""
    SELECT math::mean(age) AS avg, count() AS total
    FROM person GROUP ALL;
""");

// Or escape hatch inside LINQ:
var vips = await ctx.People
    .Where(p => p.Age > 18)
    .Raw("tags CONTAINS 'vip'")
    .ToListAsync();

Supported LINQ Operators

Key Files

Production Considerations

• Connection pooling — reuse HttpClient via IHttpClientFactory
• Parameter binding — replace string interpolation with $param placeholders to prevent SurrealQL injection
• Schema migration — wrap DEFINE TABLE / FIELD / INDEX calls in versioned migration scripts
• Live queries — use WebSocket client for LIVE SELECT subscriptions
• Auth — swap Basic auth for JWT via SIGNIN / AUTHENTICATE
• Caching — add result caching at the ISurrealQueryExecutor layer