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MCP server for secure database access (PostgreSQL, MySQL, SQLite)

Open source Open in the app JSON README (API)

About

MCP server for secure database access (PostgreSQL, MySQL, SQLite)

Details

Kind
MCP servers
Topic
Databases
Publisher
pilat
Origin
official
Category
ferramentas
Transport
local
Version
1.2.4
Stars
4
Forks
2
Last push
2026-09-05T13:30:59Z
Repository state
ativo
Language
TypeScript
License
MIT
Added
2026-08-29 04:01:01
Updated
2026-08-29 04:01:01
Origin id
io.github.pilat/mcp-datalink

README

# @pilat/mcp-datalink

MCP server for PostgreSQL, MySQL, and SQLite. Gives AI assistants secure database access via [Model Context Protocol](https://modelcontextprotocol.io).

```
npx @pilat/mcp-datalink
```

Works with Claude Desktop, Claude Code, Cursor, Cline, and any MCP-compatible client.

## Installation

Add to your MCP client config file (see [config locations](#config-file-locations) below):

```json
{
  "mcpServers": {
    "datalink": {
      "command": "npx",
      "args": ["-y", "@pilat/mcp-datalink"],
      "env": {
        "DATALINK_ANALYTICS_URL": "postgresql://user:password@localhost:5432/analytics",
        "DATALINK_ANALYTICS_READONLY": "true",

        "DATALINK_INVENTORY_URL": "mysql://user:password@localhost:3306/inventory",

        "DATALINK_CACHE_URL": "sqlite:///path/to/cache.db"
      }
    }
  }
}
```

This creates three database connections: `analytics` (read-only), `inventory`, and `cache`.

| Variable | Description |
|----------|-------------|
| `DATALINK_{NAME}_URL` | Connection URL (creates database named `{name}`) |
| `DATALINK_{NAME}_READONLY` | Set to `true` to block writes |
| `DATALINK_{NAME}_MAX_TIMEOUT` | Max query timeout in ms (caps model requests) |

**Connection URL formats:**

```bash
# PostgreSQL
postgresql://user:password@localhost:5432/dbname
postgresql://user:password@localhost:5432/dbname?sslmode=require

# MySQL
mysql://user:password@localhost:3306/dbname
mysql://user:password@localhost:3306/dbname?ssl=true

# SQLite
sqlite:///path/to/database.db
sqlite:///Users/me/data/app.sqlite
sqlite://../relative/path/data.db
```

### Environment Variable Substitution

URLs support `${VAR}` syntax to reference other environment variables:

```json
{
  "mcpServers": {
    "datalink": {
      "command": "npx",
      "args": ["-y", "@pilat/mcp-datalink"],
      "env": {
        "DATALINK_MAIN_URL": "${DATABASE_URL}"
      }
    }
  }
}
```

This allows reusing existing environment variables (like `DATABASE_URL` from your shell or `.env` file).

**Supported syntax:**

| Syntax | Description |
|--------|-------------|
| `${VAR}` | Expands to value of `VAR`, or keeps `${VAR}` if unset |
| `${VAR:-default}` | Expands to value of `VAR`, or `default` if unset |

**Examples:**

```bash
# Reference existing DATABASE_URL
DATALINK_MAIN_URL="${DATABASE_URL}"

# Build URL from parts
DATALINK_MAIN_URL="postgresql://${DB_USER}:${DB_PASS}@${DB_HOST}:5432/mydb"

# With default values
DATALINK_MAIN_URL="postgresql://localhost:${DB_PORT:-5432}/mydb"
```

### Config File Locations

| Client | Config file |
|--------|-------------|
| Claude Code | `~/.claude.json` (global) or `.mcp.json` (project) |
| Claude Desktop (macOS) | `~/Library/Application Support/Claude/claude_desktop_config.json` |
| Claude Desktop (Windows) | `%APPDATA%\Claude\claude_desktop_config.json` |
| Cursor | `~/.cursor/mcp.json` or Settings → Features → MCP Servers |
| Cline | `cline_mcp_settings.json` or VS Code settings `cline.mcpServers` |

## Tools

| Tool | Description |
|------|-------------|
| `list_databases` | List configured database connections |
| `list_tables` | List tables with row counts |
| `describe_table` | Get schema, indexes, foreign keys |
| `query` | Run SELECT queries |
| `execute` | Run INSERT/UPDATE/DELETE |
| `explain` | Show query execution plans |

## Security

- Prepared statements only (no SQL injection)
- Single statement per query (no chaining)
- DDL blocked (no DROP, ALTER, TRUNCATE)
- Readonly mode per connection
- Response size limit (100 rows, 64KB default, configurable via `DATALINK_MAX_TOTAL_SIZE`)
- Query timeout: 30s default, model can request up to 10min, `MAX_TIMEOUT` caps it

## License

MIT

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