1 Database Programming with ADO.NET Kashef Mughal

2 Last Week  We looked at the following:  OleDbConnection - active connection to the database for an OLEDB provider  DataSet - subset of the database, can be updateable  OleDbDataAdapter - data bridge between the OleDbConnection and the DataSet for an OLEDB provider  OleDbCommand - SQL command that is executed against the database

3 This Week  We are going to work with the following:  SqlConnection - active connection to the SQL Server database - carries the connection info  SqlDataAdapter - data bridge between the SqlConnection and the DataSet for a SQL Server database  SqlCommand - SQL command that is executed against the database which in this case is SQL  Why different objects for SQL Server? These are optimized for retrieving data from SQL Server

4 A few thing about SQL Server  Enterprise database from Microsoft  Comes in versions 7, 2000 and YUKON (not out yet)  Think of SQL Server as Access on steroids  Enterprise Manager is the tool of choice for SQL Server administration  Query Analyzer is the tool of choice for testing queries and SQL code  Go ahead and open Enterprise Manager from Start - Program Files - Microsoft SQL Server - Enterprise Manager

5 Enterprise Manager  Expand SQL Server Group  Expand your Server  Expand Database  Expand Northwind  Expand pubs  Select tables  Right click on Authors table and select Return all rows

6 Query Builder in EM  Click on the Show/Hide Diagram pane - Second Tool Bar button  Click on the Show/Hide Grid pane - Third Tool Bar button  Click on the Show/Hide SQL pane - Fourth Tool Bar button  Does this look familiar ?  You can use this to build your SQL and then paste it in VB.NET

7 Connection String parameters  Server - machine name  Database - e.g. Northwind  uid - username  pwd - password  Integrated Security - set to true if using Windows Authentication

8 Back to VB.NET  sqlCommand represents a SQL command that can be executed against the Database  Last week we used SELECT command  Connection property of sqlCommand represents the connection to the database  CommandText property of sqlCommand is the actual SQL command - Remember that this is a string so you will have to use double quotes  Parameter Collection is used with parameters  ExecuteNonQuery method with execute the SQL

9 sqlDataAdapter  sqlDataAdapter is similar to OleDbDataAdapter in that it is a bridge between db and Data Set  SelectCommand property is used to specify the SQL for sqlDataAdapter  Fill is the method used to populate a Data Set using sqlDataAdapter

10 Data View object  Works with the Data Set object  Difference lies in the fact that Data View can be used for sorting and filtering data  Sort property will sort the data  RowFilter property is used to return only data with a specific criteria - similar to WHERE clause

11 Exercises  Try the following ones  Page 637  Page 641  Take a break when finished

12 The Server Explorer Window  The Server Explorer can help you quickly create data driven applications as well as allow you to create SQL databases.  The Server Explorer has two nodes at the top: Data Connections and Servers.  The Data Connections node lists the databases that you've created a connection to using the data adapter wizard. The Servers node lists the db servers available to you.

13 Server Explorer Screen Shot

14 Advantages of Server Explorer  Database Administration - You can not only view the objects but can create new ones - You may not have access to Enterprise Manager and can use this tool instead  Can create multiple connections from the same window  Monitor events and counters on your machine or other servers  Minimize the code you need to write as shown in the next section

15 Advantages of Server Explorer - Part 2  We will be using pubs database on the SQL Server  Start a new Project in Vb.NEt  Drag the authors table from the Server explorer to the form  Notice it created a connection and sql adapter  Right click on sqldataadapter1 and Preview Data  Right click and select Generate DataSet (New)  Add a Data Grid to the form and set properties  Add the code to the Form Load event

16 DATA FORM WIZARD  The data form wizard allows you to quickly create a data bound form complete with the appropriate ADO.NET objects and bound controls.  To use the wizard add a new item to your project by right clicking on the application name and choosing Add-->Add New Item  This will start the wizard  Pick new data set option, call it myDS - Next  Use existing SQL connection - Next

17 DATA FORM WIZARD - Part 2  Select the employee table - Next  Make sure all the fields are selected - Next  How do you want to display data - Pick single record - Leave all the options check and select Finish  Wow - You are done  Make sure you have this DataForm1 selected as default  Run the bad boy!

18 A few more terms  Data Binding is the term used when you are using bound data control like a data grid  Binding Context object manages all the bindings of the controls on a form  It does this my managing a collection of currencymanager objects  Currency Manager is responsible for keep data consistent between objects and data source

19 Exercises  Try the following ones  Page 647  Page 659  Page 661  Take a break when finished  Remember next week is Final

20 Final  Chapter 8-16 minus Chapter 13  In-class material  Open Book, open notes  100 questions  true/false  multiple choice  a few from the midterm  200 points  2 hours  Grades right now