sql-preview

SQL Preview for VS Code

A Visual Studio Code extension for connecting to Trino databases, running SQL queries, and visualizing results directly within your editor.

Features

• SQL Query Execution: Run SQL queries against Trino databases directly from VS Code.
• Interactive Results View: View query results in a high-performance AG Grid table with sorting, filtering, and resizing.
• Code Lens Integration: Execute queries with a single click from your .sql files.
• Client-Server Architecture: Uses a dedicated background daemon for reliable connection management and query execution.
• Secure Password Storage: Passwords are encrypted using the OS keyring via VS Code's SecretStorage API.
• MCP Integration (Beta): Exposes database tools to AI agents via the Model Context Protocol.

Usage

Running Queries

• Open a .sql file.
• Code Lens: Click "Run Query" above the SQL block.
• Command Palette: Open the palette (Cmd+Shift+P) and run SQL Preview: Run Query.
• Shortcut: Press Cmd+Enter (Mac) or Ctrl+Enter (Windows/Linux) to run the query.

Viewing Results

Results appear in the SQL Preview panel.

• Sort: Click column headers.
• Filter: Use the text boxes below headers.
• Export: Right-click to copy cells.

Architecture

This extension uses a robust Client-Server model:

• Extension (Client): The VS Code frontend that handles UI, commands, and configuration.
• Daemon (Server): A separate Node.js process that manages database connections and executes queries.
• Communication: The Client and Daemon communicate via the Model Context Protocol (MCP) over local sockets.

This separation ensures that long-running queries do not block the VS Code UI and provides a stable environment for database interactions.

Configuration

Add the following configuration to your settings.json:

{
  "sqlPreview.defaultConnector": "trino",
  "sqlPreview.host": "trino-coordinator.example.com",
  "sqlPreview.port": 443,
  "sqlPreview.user": "your-username",
  "sqlPreview.catalog": "hive",
  "sqlPreview.schema": "default",
  "sqlPreview.ssl": true,
  "sqlPreview.sslVerify": true,
  "sqlPreview.maxRowsToDisplay": 1000,
  "sqlPreview.logLevel": "INFO" // Options: DEBUG, INFO, WARN, ERROR
}

Secure Password Management

For security, passwords are never stored in plain text.

• Set Password: Run the command SQL Preview: Set Database Password or click "Set Password" in the Settings UI.
• Clear Password: Run SQL Preview: Clear Stored Password.

🤖 Model Context Protocol (MCP) Integration (Beta)

This extension includes a built-in MCP server that allows AI assistants (like Claude) to interact with your database.

Enabling MCP

• Open VS Code Settings.
• Set sqlPreview.mcpEnabled to true.
• (Optional) Set sqlPreview.mcpSafeMode to true (default) to restrict AI to read-only queries.
• Restart the extension or run SQL Preview: Restart Background Server.

Available Tools

When enabled, the following tools are available to MCP clients:

• run_query: Execute a SQL query.
• list_tables: List tables in a schema.
• describe_table: Show table schema.
• get_ddl: Get the CREATE TABLE statement.

Project Structure

sql-preview/
├── src/
│   ├── extension.ts          # Main extension entry point (Client)
│   ├── server/               # Daemon process (Server)
│   │   ├── Daemon.ts         # Server entry point
│   │   └── DaemonMcpServer.ts # MCP implementation
│   ├── connectors/           # Database connectors (Trino)
│   └── ui/                   # Webview logic
└── webviews/                 # Frontend assets (React/HTML/CSS)

Development

• Clone: git clone ...
• Install: npm install
• Build: npm run build
• Debug: Press F5 to start the Extension Host.