MyEFvibe Studio — User guide

MyEFvibe Studio is a desktop LINQ scratchpad for Entity Framework Core. It runs real queries against your project's DbContext, shows translated SQL and execution plans, and helps you explore schema, scan for performance issues, and share queries with your team.

Studio uses the efvibe CLI as its evaluation engine (efvibe serve daemon). For installation and release builds, see INSTALL.md in the Studio repository.

Before you start

Prerequisites

• .NET SDK 8+
• efvibe on your PATH (or configured in Settings)

dotnet tool install --global efvibe

Studio spawns efvibe serve in the background. If prerequisites are missing, a banner at the top explains what to install.

Supported platforms

First session

1. Open or create a workspace — sidebar toolbar: New, Open, or Save for .efvibe-workspace files.
2. Configure a connection — under Connections, right-click → Edit…. Set a search directory (folder containing your solution) so efvibe can discover .csproj files.
3. Run a query — Query view, enter db.Products.Take(5).ToList();, press Run current line (Ctrl+Enter) or Run all (F5) on the query tab toolbar.
4. Inspect results — Result, SQL, Plan, and Messages tabs in the results panel.

The workspace layout

┌─────────────────────────────────────────────────────────────────┐
│  Connection bar · Main view tabs · Status bar                   │
├──────────┬──────────────────────────────────────────────────────┤
│ Explorer │  Query tabs / Notebook / Diagram / REPL               │
│          │  Per-tab toolbar: Run all · Run line · Run plan · Stop│
│          │  ┌──────┬─────────────────────────┬──────────────┐  │
│          │  │ Tool │  Editor                 │  Live SQL    │  │
│          │  │ rail │                         │  preview     │  │
│          │  └──────┴─────────────────────────┴──────────────┘  │
│          │  Results panel (Result · SQL · Plan · Messages)     │
└──────────┴──────────────────────────────────────────────────────┘

Main views

Toggle the explorer from the top bar (or customize the shortcut in Settings).

Connections

Each workspace can define multiple connections. Right-click a connection → Edit….

Connection actions

• Activate — switch active connection
• Refresh — restart the efvibe daemon
• Rebuild — force dotnet build
• DB Info — provider and server metadata
• ER Diagram — open diagram view

When Store connection strings in the local secret vault is enabled in Settings, secrets stay out of .efvibe-workspace files.

Script session & Scripts panel

Preload C# script helpers into the Roslyn session — shared filters, constants, extension methods, and extra usings.

Connection script settings

After changing script settings, Refresh the connection to restart the daemon.

Scripts tool (left rail)

Click Scripts in the editor tool rail to list .csx files in the script search path, edit with C# syntax highlighting, save, and create new files. Files marked load are configured in Script loads.

Example helpers

scripts/constants.csx

const int DefaultTake = 25;
const decimal MinListPrice = 0m;

scripts/product-filters.csx

#load "constants.csx"

IQueryable<Product> ActiveProducts() =>
    db.Products.Where(p => !p.DiscontinuedDate.HasValue && p.ListPrice > MinListPrice);

Inline #load at the top of a query tab works for one-off scripts (paths resolve against script search path).

Query view

Running queries

Each query tab has its own toolbar: connection picker, Run all, Run current line, Run plan, and Stop.

Last results stay visible while you edit; they clear when you launch Studio (fresh session).

Script attributes (#[Compare], #[Benchmark])

Attribute lines run structured experiments instead of a single evaluation. Shared code before the first attribute is prepended to every block.

#[Compare("With tracking")]
ActiveProducts().OrderBy(p => p.Name).Take(10).ToList();

#[Compare("No tracking")]
ActiveProducts().AsNoTracking().OrderBy(p => p.Name).Take(10).ToList();

#[Benchmark(10)]
ActiveProducts().AsNoTracking().OrderBy(p => p.Name).Take(10).ToList();

Use Run all (F5). Compare and benchmark output appears in the Result tab. Live SQL preview is skipped for attributed scripts.

Three query styles

1. Raw SQL — paste SELECT, WITH, etc. Editor switches to SQL highlighting; executed directly (not EF translation).

SELECT TOP 10 ProductID, Name, ListPrice
FROM Products AS p
WHERE p.ListPrice > 0
ORDER BY p.Name;

2. Fluent LINQ — method syntax on db DbSets:

db.Products
  .Where(p => p.Name.Contains("Helmet"))
  .OrderBy(p => p.Name)
  .Take(10)
  .Select(p => new { p.ProductId, p.Name, p.ListPrice })
  .ToList();

3. Query comprehension — from / where / select syntax:

from product in db.Products
where product.ListPrice > 0
orderby product.Name
select product;

Using project types

Types from assemblies referenced by your EF project (-p) are available in queries. efvibe auto-imports namespaces (except System.* / Microsoft.*). Add namespaces under Additional usings or use fully qualified names. After adding types, Refresh or Rebuild the connection.

Results panel

Live SQL preview

Toggle the Linq/Sql pane on the right for debounced ToQueryString() as you type (plain LINQ; skipped when the script contains #[ attributes), or paste SQL for a draft LINQ expression (sqlToLinq, efvibe 0.6.13+).

Editor tools

Vertical tool rail to the left of the query editor:

Use #[Benchmark(N)] with Run all (F5) for timed runs; results appear in the Result tab.

Explorer sidebar

• Workspace — New / Open / Save workspace files
• Connections → Model — DbSet tree; Query, Sample, Count, Describe, ER diagram from context menus
• Team — Export/import team packs, sync folder push/pull, cloud sync, git commit for efvibe files

Connection strings are never included in packs or cloud sync.

ER Diagram view

Mermaid entity-relationship diagram for the active connection. Open from the main view switcher, connection menu, or a DbSet. Filter by entity from the dropdown.

Notebook view

Multi-cell scratchpad saved as .efvibe-notebook.

• Code cells — LINQ, raw SQL, or commands (:dbinfo, :tables)
• Markdown cells — documentation; click to edit
• Run all, run above/below per cell, Add above/below, Save as…

Notebook runs do not appear in query History or Charts (by design).

REPL view

Embedded terminal running efvibe repl for the active connection. Type :help for commands. Use Open external terminal for your system terminal.

Team sharing and sync

• Team packs (.efvibe-pack) — queries, snippets, folders via Team → Export/Import
• Sync folder — push/pull favorites to a shared directory (Settings → Team sync directory)
• Cloud sync — Dropbox, iCloud, OneDrive folder for favorite queries
• Git — commit .efvibe-workspace, .efvibe-query, .efvibe-notebook from Team → Git

Settings

Gear icon in the explorer footer.

File formats

Keyboard shortcuts

Defaults (customizable in Settings):

Tips and troubleshooting

Prerequisites banner

Install .NET SDK and efvibe; configure tool path in Settings if not on PATH.

Daemon / handshake errors

Refresh or Rebuild the connection. Ensure efvibe is recent enough for Studio features (script session, sqlToLinq). Check connection fields (EF project, startup, context).

Script load file not found

Verify Script search path (default scripts/ beside workspace file). Use relative names in Script loads (constants.csx, not paths under the EF project). Refresh after editing scripts.

Build failures

Fix compile errors in the EF project first. Try Rebuild and confirm framework matches your project (net8.0, net10.0, etc.).

Type or namespace not found

Confirm the type is in an assembly referenced by the EF project. Add Additional usings or use a fully qualified name. Rebuild after project changes.

Stale SQL or results

Refresh restarts the daemon. Script edits require refresh to reload .csx files.

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