What is ACCDB?

ACCDB (Access Database) is the modern Access format replacing MDB with Access 2007. It uses the ACE (Access Connectivity Engine) instead of Jet Database Engine, supporting larger databases (32 GB vs 2 GB), stronger 128-bit RC4 encryption, attachment fields for storing files, multi-valued fields, append-only memo fields, and calculated columns. ACCDB cannot be opened by Access 2003 or earlier versions.

ACCDB is used for modern Access applications, small business databases, departmental applications, rapid prototyping, and legacy system migrations from MDB. It's the default format for Access 2007, 2010, 2013, 2016, 2019, 2021, and Microsoft 365. While Access remains popular for departmental solutions, larger organizations often migrate to SQL Server, Azure SQL, or cloud databases for better scalability and web integration.

Did you know? ACCDB can store up to 32 GB - 16 times larger than old MDB format!

History

Microsoft developed ACCDB to overcome MDB limitations and modernize Access with new features, better security, and improved data types.

Key Milestones

  • 2007: ACCDB format introduced with Office 2007
  • 2010: Enhanced macro security
  • 2013: Office 365 integration
  • 2016: Large Number data type
  • 2019: SharePoint improvements
  • Present: Current Access standard

Key Features

Core Capabilities

  • 32 GB Limit: Much larger databases
  • Enhanced Encryption: 128-bit RC4
  • Attachment Fields: Store files in database
  • Multi-Valued: Multiple values per field
  • Calculated Columns: Formula-based fields
  • ACE Engine: Modern database engine

Common Use Cases

Business Apps

Modern business databases

Teams

Department solutions

Prototyping

Rapid application development

Reporting

Data analysis and reports

Advantages

  • Much larger file size (32 GB)
  • Stronger encryption security
  • Attachment and multi-valued fields
  • Modern database engine
  • Calculated columns
  • Better corruption recovery
  • Still easy to use

Disadvantages

  • Not backwards compatible with 2003
  • Still Windows-only
  • Poor for web applications
  • Limited concurrent users
  • Desktop-oriented architecture
  • Proprietary Microsoft format

Technical Information

Format Specifications

Specification Details
File Extension .accdb
MIME Type application/x-msaccess
Max File Size 32 GB (2 GB recommended)
Database Engine ACE (Access Connectivity Engine)
Encryption 128-bit RC4
Access Versions 2007, 2010, 2013, 2016, 2019, 2021

Common Tools

  • Microsoft Access: 2007-2021, Microsoft 365
  • Runtime: Access Runtime (free distribution)
  • Programming: ACE ODBC, OleDB, ADO.NET
  • Migration: SQL Server Migration Assistant