OpenLink MCP Server for JDBC

A lightweight Java-based MCP (Model Context Protocol) server for JDBC built with Quakrus. This server is compatible with Virtuoso DBMS and any other DBMS backend that has a JDBC driver.

Features

• Get Schemas: Fetch and list all schema names from the connected database.
• Get Tables: Retrieve table information for specific schemas or all schemas.
• Describe Table: Generate a detailed description of table structures, including:
  • Column names and data types
  • Nullable attributes
  • Primary and foreign keys
• Search Tables: Filter and retrieve tables based on name substrings.
• Execute Stored Procedures: A Virtuoso-specific feature! Execute stored procedures and retrieve results.
• Execute Queries:
  • JSONL result format: Optimized for structured responses.
  • Markdown table format: Ideal for reporting and visualization.

Prerequisites

MCP server requires Java 21 or above.

Installation

Clone this repository:

git clone https://github.com/OpenLinkSoftware/mcp-jdbc-server.git  
cd mcp-jdbc-server

Environment Variables

Update your .env by overriding these defaults to match your preferences:

jdbc.url=jdbc:virtuoso://localhost:1111
jdbc.user=dba
jdbc.password=dba
jdbc.api_key=xxx

Configuration

For Claude Desktop users using Virtuoso and its JDBC driver:

Add the following to claude_desktop_config.json:

{
  "mcpServers": {
    "my_database": {
      "command": "java",
      "args": ["-jar", "/path/to/mcp-jdbc-server/MCPServer-1.0.0-runner.jar"],
      "env": {
        "jdbc.url": "jdbc:virtuoso://localhost:1111",
        "jdbc.user": "username",
        "jdbc.password": "password",
        "jdbc.api_key": "sk-xxx"
      }
    }
  }
}

For Claude Desktop users using another JDBC driver or a combination of drivers:

Add the following, edited to suit your local environment, to claude_desktop_config.json:

    "jdbc": {
      "command": "java",
      "args": [
        "-cp",
        "/path/to/mcp-jdbc-server/MCPServer-1.0.0-runner.jar:/path/to/jdbc_driver1.jar:/path/to/jdbc_driverN.jar",
        "io.quarkus.runner.GeneratedMain"
      ],
      "env": {
        "jdbc.url": "jdbc:virtuoso://localhost:1111",
        "jdbc.user": "dba",
        "jdbc.password": "dba"
      }
    }

Use

Tools Provided

After successful installation, the following tools will be available to MCP client applications.

Overview

Detailed Description

• jdbc_get_schemas

  • Retrieve and return a list of all schema names from the connected database.
  • Input parameters:
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns a JSON string array of schema names.

• jdbc_get_tables

  • Retrieve and return a list containing information about tables in a specified schema. If no schema is provided, uses the connection's default schema.
  • Input parameters:
    • schema (string, optional): Database schema to filter tables. Defaults to connection default.
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns a JSON string containing table information (e.g., TABLE_CAT, TABLE_SCHEM, TABLE_NAME, TABLE_TYPE).

• jdbc_filter_table_names

  • Filters and returns information about tables whose names contain a specific substring.
  • Input parameters:
    • q (string, required): The substring to search for within table names.
    • schema (string, optional): Database schema to filter tables. Defaults to connection default.
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns a JSON string containing information for matching tables.

• jdbc_describe_table

  • Retrieve and return detailed information about the columns of a specific table.
  • Input parameters:
    • schema (string, required): The database schema name containing the table.
    • table (string, required): The name of the table to describe.
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns a JSON string describing the table's columns (e.g., COLUMN_NAME, TYPE_NAME, COLUMN_SIZE, IS_NULLABLE).

• jdbc_query_database

  • Execute a standard SQL query and return the results in JSON format.
  • Input parameters:
    • query (string, required): The SQL query string to execute.
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns query results as a JSON string.

• jdbc_query_database_md

  • Execute a standard SQL query and return the results formatted as a Markdown table.
  • Input parameters:
    • query (string, required): The SQL query string to execute.
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns query results as a Markdown table string.

• jdbc_query_database_jsonl

  • Execute a standard SQL query and return the results in JSON Lines (JSONL) format (one JSON object per line).
  • Input parameters:
    • query (string, required): The SQL query string to execute.
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns query results as a JSONL string.

• jdbc_spasql_query

  • A Virtuoso-specific feature!
  • Execute a SPASQL (SQL/SPARQL hybrid) query return results.
  • Input parameters:
    • query (string, required): The SPASQL query string.
    • max_rows (number, optional): Maximum number of rows to return. Defaults to 20.
    • timeout (number, optional): Query timeout in milliseconds. Defaults to 30000 (i.e., 30 seconds).
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns the result from the underlying stored procedure call (e.g., Demo.demo.execute_spasql_query).

• jdbc_sparql_query

  • A Virtuoso-specific feature!
  • Execute a SPARQL query and return results.
  • Input parameters:
    • query (string, required): The SPARQL query string.
    • format (string, optional): Desired result format. Defaults to 'json'.
    • timeout (number, optional): Query timeout in milliseconds. Defaults to 30000 (i.e., 30 seconds).
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns the result from the underlying function call (e.g., "UB".dba."sparqlQuery").

• jdbc_virtuoso_support_ai

  • A Virtuoso-specific feature!
  • Utilizes a Virtuoso-specific AI Assistant function, passing a prompt and optional API key.
  • Input parameters:
    • prompt (string, required): The prompt text for the AI function.
    • api_key (string, optional): API key for the AI service. Defaults to "none".
    • user (string, optional): Database username. Defaults to "demo".
    • password (string, optional): Database password. Defaults to "demo".
    • url (string, optional): JDBC URL connection string.
  • Returns the result from the AI Support Assistant function call (e.g., DEMO.DBA.OAI_VIRTUOSO_SUPPORT_AI).

Basic Use & Troubleshooting

MCP Inspector Connecting to Virtuoso's ODBC Driver

For basic MCP client use and troubleshooting, use the MCP Inspector as follows:

1. Install the MCP Inspector:

   Terminal

   Copy

   npm install -g @modelcontextprotocol/inspector
   

2. Start the inspector: