ADO.NET 3.5 Cookbook, 2nd Edition

7.10. Resolving Data Conflicts

Problem

You need to effectively resolve data conflicts and prevent overwriting of existing data when attempting to update changes in a DataSet to a database where the underlying data has changed.

Solution

Handle the DBConcurrencyException within the RowUpdated event of the DataAdapter.

The solution uses a table named ResolveDataConflict in the database AdoDotNet35Cookbook. Execute the following T-SQL statement to create the table:

	USE AdoDotNet35Cookbook
	GO
	CREATE TABLE ResolveDataConflict(
	    Id int NOT NULL PRIMARY KEY,
	    Field1 nvarchar(50) NULL,
	    Field2 nvarchar(50) NULL )

The schema of table ResolveDataConflict is shown in Table 7-6.

Table 7-6. ResolveDataConflict table schema

Column name	Data type	Length	Length
Id	int	4	No
Field1	nvarchar	50	Yes
Field2	nvarchar	50	Yes

Execute the following T-SQL statement to create some sample data for the solution:

	USE AdoDotNet35Cookbook
	GO
	INSERT INTO ResolveDataConflict VALUES (1, 'Field1.1', 'Field2.1');
	INSERT INTO ResolveDataConflict VALUES (2, 'Field1.2', 'Field2.2');
	INSERT INTO ResolveDataConflict VALUES (3, 'Field1.3', 'Field2.3');

The solution creates a DataTable named User 1 and fills it with the schema and data in the table ResolveDataConflict in the AdoDotNet35Cookbook database. The ContinueUpdateOnError property of the DataAdapter is set to true. A handler named daUser1_RowUpdated is assigned to the RowUpdated event of the DataAdapter. A CommandBuilder object is created to generate the updating logic for the DataAdapter.