JetDatabaseReader 1.0.0

JetDatabaseReader

Pure-managed .NET library for reading Microsoft Access JET databases without requiring OleDB, ODBC, or ACE drivers.

Features

• ✅ No Dependencies - Pure C# implementation, no native drivers required
• ✅ Jet3 & Jet4+ - Supports Access 97 (.mdb) through Access 2019 (.mdb/.accdb)
• ✅ All Data Types - Text, Integer, Date, GUID, Currency, MEMO, OLE Object
• ✅ Streaming API - Process millions of rows without out-of-memory errors
• ✅ Page Caching - 256-page LRU cache for 50%+ performance boost
• ✅ Progress Reporting - IProgress<int> callbacks for long operations
• ✅ Multi-Language - Auto-detects code page (Cyrillic, Japanese, etc.)
• ✅ OLE Objects - Auto-detects embedded images, PDFs, Office docs

Installation

dotnet add package JetDatabaseReader

Or via Package Manager Console:

Install-Package JetDatabaseReader

Quick Start

using JetDatabaseReader;

// Open database
using (var reader = new JetDatabaseReader("database.mdb"))
{
    // List all tables
    var tables = reader.ListTables();
    Console.WriteLine($"Found {tables.Count} tables");

    // Read a table (first 100 rows)
    var (headers, rows, schema) = reader.ReadTable("MyTable", maxRows: 100);
    foreach (var row in rows)
    {
        Console.WriteLine(string.Join(", ", row));
    }
}

Usage Examples

Stream Large Tables

using (var reader = new JetDatabaseReader("large.mdb"))
{
    var progress = new Progress<int>(count => 
        Console.WriteLine($"Processed {count} rows"));

    foreach (var row in reader.StreamRows("BigTable", progress))
    {
        // Process one row at a time - no memory issues
        ProcessRow(row);
    }
}

Read as DataTable

using (var reader = new JetDatabaseReader("data.mdb"))
{
    DataTable dt = reader.ReadTableAsDataTable("Customers");
    
    // Bind to DataGridView, export to CSV, etc.
    dataGridView1.DataSource = dt;
}

Get Table Statistics

using (var reader = new JetDatabaseReader("db.mdb"))
{
    var stats = reader.GetTableStats();
    foreach (var (name, rowCount, columnCount) in stats)
    {
        Console.WriteLine($"{name}: {rowCount} rows, {columnCount} columns");
    }
}

Enable Performance Features

var reader = new JetDatabaseReader("database.mdb")
{
    PageCacheSize = 512,              // Increase cache (default: 256)
    ParallelPageReadsEnabled = true,  // Parallel I/O (default: false)
    DiagnosticsEnabled = true         // Debug output (default: false)
};

Limitations

• ❌ Encrypted databases - Remove password in Access first (File > Info > Encrypt with Password)
• ❌ Attachment fields (Type 0x11) - Rare, added in Access 2007
• ❌ Linked tables - Only local tables are returned
• ❌ Write operations - Read-only library

Compatibility

• .NET Standard 2.0 - Compatible with:
  • .NET Framework 4.6.1+
  • .NET Core 2.0+
  • .NET 5/6/7/8+
  • Xamarin, Unity, UWP

How It Works

Based on the mdbtools format specification, this library directly parses JET database pages without requiring Microsoft drivers. It handles:

• Database header parsing (Jet3/Jet4 detection)
• MSysObjects catalog scanning
• TDEF (table definition) page chains
• Data page traversal
• LVAL (long value) chains for MEMO/OLE fields
• Compressed Unicode text (Jet4)
• Code page detection for non-Western text

Contributing

Contributions are welcome! Please open an issue or submit a pull request.

License

MIT License - see LICENSE for details

Acknowledgments

Format specification based on mdbtools by Brian Bruns and contributors.