mdf-rs

Rust parser for the mdf file format used by Microsoft SQL Server.

Features

• low level parsing of pages and records
• parsing of system tables
  • parsing of existing tables
  • parsing of table schema
• reading table rows
• reading LOB data storage
• larger than memory files
• data recovery from broken files
• supported datatypes
  • tinyint, smallint, int, bigint
  • binary(n), char(n), nchar(n)
  • varbinary(n), varchar(n), nvarchar
  • bit
  • sqlvariant
  • sysname
  • datetime, smalldatetime
  • uniqueidentifier
  • image
  • ntext
  • float

Usage

This crate provides only parsing functionality, for flexibility all pages have to be provided by implementing the PageProvider trait.

You can find a example implementation for reading directly from Microsoft SQL Server backup files in the mtf crate.

Access on the Page and Record level is available from the PageProvider::get and the RawPage::records API.

The system tables are parsed by DB::new and then used to provide a list of existing Tables with DB::tables.

The rows of a Table can be read using Table::rows and basic data recovery can be performed using Table::scan_db.

Included are additionally three examples:

1. lob_dumper scans the whole database for rows entries stored as LOB data and dumps them into files.
2. p_min_len_dumper performs a basic for of data recovery by using the p_min_len field of Pages to associate each Page in the database with its corresponding Table.
3. sharepoint_dump dumps all files stored in a sharepoint database to disk, extracting the names / paths from the AllDocs table and their content from AllDocStreams.

Why not oxidized-mdf?

I was very delighted to find a existing implementation of a mdf file format parser at https://gitlab.com/schrieveslaach/oxidized-mdf, however in the end I decided to implement a version myself due to multiple reasons:

1. oxidized-mdf contains multiple subtle errors, finding them all might be hard
2. oxidized-mdf is unsuitable for larger than memory files as is
3. implementing a async interface as oxidized-mdf strives do to is hard while supporting larger than memory files

References

The documentation of the mdf format from the following sources was used:

[1] https://github.com/improvedk/OrcaMDF

[2] https://www.sqlskills.com/blogs/paul/category/inside-the-storage-engine/

[3] http://www.kazamiya.net/en/mssql_4n6-01

[4] https://gitlab.com/schrieveslaach/oxidized-mdf