Rapidly Develop DB2-Driven Apps with Active Query Builder

Write standard .NET to expose DB2 data through an SQL interface: Active Query Builder helps developers write SQL interfaces; the CData ODBC Driver for DB2 enables standards-based access to DB2. This integration uses the Microsoft ADO.NET Provider for ODBC as a bridge between the ODBC Driver and the Active Query Builder objects to build a visual SQL composer.

Connect to DB2 as an ODBC Data Source

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

Set the following properties to connect to DB2:

• Server: Set this to the name of the server running DB2.
• Port: Set this to the port the DB2 server is listening on.
• Database: Set this to the name of the DB2 database.
• User: Set this to the username of a user allowed to access the database.
• Password: Set this to the password of a user allowed to access the database.

You will also need to install the corresponding DB2 driver:

• Windows: Install the IBM Data Server Provider for .NET.

  On Windows, installing the IBM Data Server Provider is sufficient, as the installation registers it in the machine.config.

• Java: Install the IBM Data Server Driver for JDBC.

  In the Java version, place the IBM Data Server Driver JAR in the www\WEB-INF\lib\ folder for this application.

Use SQL to Interact with DB2

Follow the steps below to create a WinForms visual query builder.

1. In a new Windows Forms project, drag the QueryBuilder from the Toolbox onto the form.
2. Add a reference to ActiveQueryBuilder.ODBCMetadataProvider.
3. Add an OdbcConnection and set the connection string to the DSN that you created in the first section. OdbcConnection connection = new OdbcConnection(); connection.ConnectionString = "DSN=DB2"
4. Initialize ODBCMetadataProvider and GeneralSyntaxProvider instances and set the Connection property of the ODBCMetadataProvider object to the OdbcConnection. GenericSyntaxProvider syntaxProvider = new GenericSyntaxProvider(); ODBCMetadataProvider metadataProvider = new ODBCMetadataProvider(); metadataProvider.Connection = connection;
5. Set the corresponding MetadataProvider and SyntaxProvider properties of the QueryBuilder object. queryBuilder1.MetadataProvider = metadataProvider; queryBuilder1.SyntaxProvider = syntaxProvider;
6. Call the InitiatelizeDatabaseSchemaTree method of the QueryBuilder class to retrieve DB2 metadata and generate a tree view of DB2 tables. queryBuilder1.InitializeDatabaseSchemaTree();

7. After creating the QueryBuilder, connect it to a TextBox or, as we use, the ActiveQueryBuilder SQLTextEditor: Drag and drop an SQLTextEditor onto the designer.

8. Add the following code to the Validating event for the SQLTextEditor: private void sqlTextEditor1_Validating(object sender, CancelEventArgs e) { try { // Update the query builder with manually edited query text: queryBuilder1.SQL = sqlTextEditor1.Text; } catch (SQLParsingException ex) { e.Cancel = true; // Set caret to error position sqlTextEditor1.SelectionStart = ex.ErrorPos.pos; // Report error MessageBox.Show(ex.Message, "Parsing error"); } }
9. Add the following to the SQLUpdated event: private void queryBuilder1_SQLUpdated(object sender, EventArgs e) { sqlTextEditor1.Text = queryBuilder1.FormattedSQL; }

10. You can now build queries visually: Double-click a table in the Columns Pane Area and an entity/relationship diagram is displayed in the Query Building Area. Columns that you select in the diagram are added to the query.