Understanding and Using System.Transactions

These are some resources to help grasp System.Transactions functionality and use it effectively in your projects:

Features Provided by System.Transactions
Implementing an Implicit Transaction using Transaction Scope
MSDN Articles by John Papa
ADO.NET and System.Transactions
Revisiting System.Transactions
These are specific to TransactionScope (the way to go in most cases)
Here is a practical example of Using TransactionScope :
This one gets in depth with the way a TransactionScope like functionality can be implemented. Gives you a good understanding of what is happening under the hood when using TransactionScope in some Repository implementations in multi-threaded scenarios.
Here is another example of implementing a transactional repository :
There are excellent tips here about configuring TransactionScope when used with SQL Server:
This is a good resource for CommitableTransaction usage – http://www.codeproject.com/Articles/55472/Committable-Transactions-in-C-SQL
And this one has brilliant under-the-hood coverage – http://www.codeproject.com/Articles/35087/Truly-Understanding-NET-Transactions-and-WCF-Impl

Using DbUpdater with MySql

DbUpdater can be used with mysql.

Here are the files you need to jumpstart the integration – DbUpdater-MySql.zip

1. You might need to change the path to mysql.exe in mysql-exec.bat.

2. Modify values in mysql-sample-command-line.bat.

Make sure mysql.data.dll is placed in GAC or in the same directory as DbUpdater.exe. Connector binaries can be downloaded from here –

Using NHibernate With SQLite in DbUpdater

DbUpdater (version 1.3 onwards) can be used with sqlite3.

Review the files included in DbUpdater-sqlite3.zip

1. DbUpdater.exe.config must be modified. Note changes to the following keys – exe-file, exe-args, dialect, driver_class, connetion_string.
2. SchemaVersion.hbm.xml must be modified. The ‘class’ attributes value for the ‘generator’ of ‘id’ must be changed to ‘identity’. No other changes are needed here.
3. \SqlScripts\schema-version-table.sql is modified. Note that the datatypes of all columns are changed to TEXT, except for SchemaChangeId, which is changed to integer primary key. integer primary key is used for auto-incremented columns in sqlite.
4. \SqlScripts\baseline.sql is modified. Note the use of current_timestamp function. The actual sql syntax in this file must conform to sqlite dialect.
5. All other .sql scripts in \SqlScripts directory are also modified to conform to sqlite dialect.

The following files are expected to be in DbUpdater.exe directory (as configured in the DbUpdater.exe.config file) –

1. sqlite3.exe : download.
2. System.Data.SQLite.dll : download.
3. createdb.bat file : This file is included. This batch script will call sqlite3.exe to execute sql queries.

Another very useful tool for working with sqlite database files is SQLite Database Browzer.

WPF – LINQ to SQL Sample

This exercise in binding a WPF ListView control with LINQ to SQL was a lot of fun ! The following image shows data from AdventureWorks sample database displayed in the ListView control. The end result is very admirable, even in this very basic demo. Feeling a complete sense of freedom is unavoidable when working with WPF.


This sample demonstrates :

  1. LINQ to SQL mapping.
  2. WPF ListView Control DataBinding.
  3. Displaying images stored in database as varbinary in WPF control.

The sample code can be downloaded here : WPF-LINQ to SQL Sample
License : Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.

Creative Commons License

Database Schema Version Control Tool

It is essential to treat database schema as source code and apply all the norms and best practices applicable to it. From what I hear and read, database schema version control is non-existent in too many projects.

Various techniques to accomplish version control of database schemas have been discussed and published. Martin Fowler and Pramod Sadagale has written a comprehensive article on Evolutionary Database Design. It is a must-read for everyone involved with database development.

K. Scott Allen writes in detail about an excellent system here – Versioning Databases – Change Scripts. This approach is sufficiently light-weight (for my taste) and provides complete control over the whole process.

I am providing a free tool here that you can use to implement this system. It will even create the SchemaVersionsLog table for your database, if it doesn’t exist. If you are using this tool with MSSQL Server, you can get started with very little effort. If you are using a different DBMS, you can still use this tool. It uses NHibernate to access the SchemaVersionsLog table. So, any DBMS supported by NHibernate is acceptable, as long as it comes with a command line tool to execute the sql scripts.

Download DbUpdater here.