1. ADO.Net and Stored ProceduresBy
Radhika Malladi

2. Introduction ADO.Net : database API, used for managed applications
It consists of a set of classes
Integrates with XML
It provides components for creating distributed, data-sharing applications
It is used to connect to data source for retrieving, updating and manipulating data.

3. Introduction cont.
Data providers are used to connect to the database, to execute commands and retrieving results
ADO.Net provides two data providers
SQL Server .Net provider – Interfaces MicrosoftSQLServer with Managed applications(System.data.SqlClient)
OLE DB .Net provider – Interfaces databases with UnManaged OLE DB providers(System.data.OleDb)

4. Design Goals ADO.Net is designed to meet the following goals:
Leverage current ADO knowledge
Support N-tier programming model
("Any number of levels arranged above another, each serving distinct and separate tasks.“)
Done by using Data Set because Data Set works well with all providers
Integrating XML

5. ADO.Net Components Two main components:
Data Set – disconnected architecture of ADO.Net
.Net data provider components – for data manipulation and read-only access to data
Connection – to make connections to database
Command – access to database commands
Data Reader – provides stream of data from data source
Data Adapter – bridge between Data Set object and data source

6. Architecture

7. .Net provider Components
Connection :
SqlConnection conn = new SqlConnection     ("server=localhost;database=a1;uid=sa;pwd=");
SqlConnection conn = new SqlConnection     ("server=xyz\malladi;database=a1;uid=sa;pwd=");
SqlConnection conn = new SqlConnection     ("server=xyz\malladi;database=a1;uid=sa;pwd=;min pool size=10;max pool size=50;connect timeout=10;Integrated Security = false;Pooling = true;");
OleDbConnection conn = new OleDbConnection     
("provider=sqloledb;data source=localhost;OLE DB Services=-2" +     "initial catalog=a1;user id=sa;password=");

8. .Net Components cont. Command:
SqlCommand cmd = new SqlCommand ("select * from users", conn);
Properties: CommadTimeout , CommandText
Methods:
ExecuteNonQuery() – This returns number of rows affected
Ex: Insert, Delete, Update (no return values)
ExecuteScalar() – single row, single column values
Ex: count, min, max, sum, avg etc and to retrive BLOBs
ExecuteReader()

9. .Net Components cont. Data Reader:
SqlDataReader reader = cmd.ExecuteReader ();
ExecuteReader() – obtains query results quickly for read-only.
Ex: Select
reader.close();
Methods:
GetName – retrieve field names
GetValue – retrieve field values(returns obj)
GetOrdinal – converts field name into numeric index

10. .Net Components cont. Data Adapter:
SqlDataAdapter adapter = new SqlDataAdapter ("select * from users",     "server=localhost;database=a1;uid=sa;pwd=");

11. Example (ExecuteReader)
SqlConnection con = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=C:\\Inetpub\\wwwroot\\Assign2\\App_Data\\a2.mdf;Integrated Security=True;User Instance=True");
try {
con.Open();
SqlCommand cmd = new SqlCommand("select role from users where username = '" + TextBox1.Text.Trim() + "' and password = '" + TextBox2.Text.Trim() + "'", con);
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
role = dr.GetString(dr.GetOrdinal("role"));
break; }
catch (SqlException ex)
Response.Write(ex.Message);
finally
con.Close();

12. Example (ExecuteScalar)
SqlConnection connection = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=c:\\inetpub\\wwwroot\\Assign2\\App_Data\\a2.mdf;Integrated Security=True;User Instance=True");
try{
connection.Open();
StringBuilder builder = new StringBuilder();
builder.Append("select count (*) from users where username = \'");
builder.Append(username);
builder.Append("\' and cast (rtrim (password) as varbinary) = cast (\'");
builder.Append(password);
builder.Append("\' as varbinary)");
SqlCommand command = new SqlCommand(builder.ToString(),connection);
int count = (int)command.ExecuteScalar();
return (count > 0); }
catch (SqlException) {
return false; }
finally {
connection.Close(); }

13. Example (ExecuteNonQuery)
SqlConnection con = new SqlConnection("Data Source=.\\SQLEXPRESS;AttachDbFilename=C:\\Inetpub\\wwwroot\\Assign2\\App_Data\\a2.mdf;Integrated Security=True;User Instance=True");
try {
con.Open();
SqlCommand cmd = new SqlCommand("insert into users (username,password,role)values('" + TextBox6.Text.Trim() + "','" + TextBox7.Text.Trim() + "','" + DropDownList1.SelectedValue + "')", con);
int noofrows = cmd.ExecuteNonQuery();
if (noofrows != 0)
Response.Write("user created successfully");
} catch (SqlException ex)
{ Response.Write(ex.Message); }
finally {
con.Close(); }

14. Data Set and Data Adapters
Set based access – captures query into memory and supports traversal through result set
This has 2 classes
Data Set : in-memory database
Data Adapter : bridge between Data Set and data source
Perform database queries
create DataTables containing query results
Capable of writing changes made to data tables back to database

15. Data Adapter Two versions: SqlDataAdapter and OleDbDataAdapter
Main Methods of Data Adapter are Fill and Update
Namespace – system.data.common.DbDataAdapter

16. Data Adapter cont. Fill:
SqlDataAdapter adapter = new SqlDataAdapter ("select * from users",     "server=localhost;database=a1;uid=sa;pwd="); DataSet ds = new DataSet ();
adapter.Fill (ds, “users");
Update :
adapter.Update (table);
Builder for Insert, Update, Delete:
SqlCommandBuilder builder = new SqlCommandBuilder (adapter);

17. Data Set
DataSet object – supports disconnected, distributed data with ADO.Net
Can be used with multiple and differing data sources
It represents complete set of data like related tables, constraints and relationships among tables

18. Data Set cont.

19. Data Set cont. DataTable Collection : contains collection of tables
DataRelationCollection: contains relationships of tables
ExtendingProperties: Property Collection where customized information can be placed
Ex: Date/Time when data is generated

20. Example to insert records
SqlDataAdapter adapter = new SqlDataAdapter ("select * from titles", "server=localhost;database=pubs;uid=sa;pwd="); DataSet ds = new DataSet (); adapter.Fill (ds, "Titles"); // Create a new DataRow DataTable table = ds.Tables["Titles"]; DataRow row = table.NewRow (); // Initialize the DataRow row["title_id"] = "JP1001"; row["title"] = "Programming Microsoft .NET"; row["price"] = "59.99"; row["ytd_sales"] = " "; row["type"] = "business"; row["pubdate"] = "May 2002"; // Add the DataRow to the DataTable table.Rows.Add (row);

21. Examples to select records
DataRow[] rows = table.Select ("title_id = 'JP1001'");
DataRow[] rows = table.Select ("price < 10.00");
DataRow[] rows = table.Select ("pubdate >= '#1/1/2000#'");
DataRow[] rows = table.Select ("state in ('ca', 'tn', 'wa')");
DataRow[] rows = table.Select ("state like 'ca*'");
DataRow[] rows = table.Select ("isnull (state, 0) = 0");
DataRow[] rows = table.Select ("state = 'tn' and zip like '37*'");

22. Example to update records
SqlDataAdapter adapter = new SqlDataAdapter ("select * from titles", "server=localhost;database=pubs;uid=sa;pwd="); DataSet ds = new DataSet (); adapter.Fill (ds, "Titles"); DataRow[] rows = table.Select ("ytd_sales > 10000"); foreach (DataRow row in rows) row["price"] = (decimal) row["price"] m;

23. Example to delete records
SqlDataAdapter adapter = new SqlDataAdapter ("select * from titles", "server=localhost;database=pubs;uid=sa;pwd="); DataSet ds = new DataSet (); adapter.Fill (ds, "Titles"); DataRow[] rows = table.Select ("ytd_sales < OR isnull (ytd_sales, 0) = 0"); foreach (DataRow row in rows) row.Delete ();

24. Example for Updating the database
SqlDataAdapter adapter = new SqlDataAdapter ("select * from titles", "server=localhost;database=pubs;uid=sa;pwd="); SqlCommandBuilder builder = new SqlCommandBuilder (adapter); DataSet ds = new DataSet (); adapter.Fill (ds, "Titles"); // Insert a record DataTable table = ds.Tables["Titles"]; DataRow row = table.NewRow (); row["title_id"] = "JP1001"; row["title"] = "Programming Microsoft .NET"; row["price"] = 59.99m; row["ytd_sales"] = ; row["type"] = "business"; row["pubdate"] = new DateTime (2002, 5, 1); table.Rows.Add (row); // Update the database adapter.Update (table);

25. Stored Procedures User defined command added to a database
Executes faster as they are already complied
Improves performance
ADO.Net supports stored procedures
An Example of stored procedure is..

26. CREATE PROCEDURE char char (10) AS BEGIN TRANSACTION UPDATE Accounts SET Balance = WHERE Account_ID IF = 0 BEGIN ROLLBACK TRANSACTION RETURN END UPDATE Accounts SET Balance = Balance WHERE Account_ID IF = 0 BEGIN RETURN END COMMIT TRANSACTION GO

27. catch (SqlException ex) { // TODO: Handle the exception }
SqlConnection conn = new SqlConnection     ("server=localhost;database=mybank;uid=sa;pwd=");
try {     
conn.Open ();   
  SqlCommand cmd = new SqlCommand ("proc_TransferFunds", conn);
    cmd.CommandType = CommandType.StoredProcedure;     
    cmd.ExecuteNonQuery (); }
catch (SqlException ex) {     // TODO: Handle the exception }
finally {     conn.Close (); }

28. Transacted Commands Example
SqlConnection conn = new SqlConnection ("server=localhost;database=mybank;uid=sa;pwd="); try { conn.Open (); // Debit $1,000 from account 1111 SqlCommand cmd = new SqlCommand ("update accounts set balance = balance where account_id = '1111'", conn); cmd.ExecuteNonQuery (); // Credit $1,000 to account 2222 cmd.CommandText = "update accounts set balance = " + "balance where account_id = '2222'"; cmd.ExecuteNonQuery (); } catch (SqlException ex) { // TODO: Handle the exception } finally { conn.Close (); }

29. Transacted Commands Example
SqlTransaction trans = null; SqlConnection conn = new SqlConnection     ("server=localhost;database=mybank;uid=sa;pwd=");
try {     conn.Open ();
    // Start a local transaction
    trans = conn.BeginTransaction (IsolationLevel.Serializable);   
  // Create and initialize a SqlCommand object
    SqlCommand cmd = new SqlCommand ();
    cmd.Connection = conn;     cmd.Transaction = trans;  
   // Debit $1,000 from account 1111  
   cmd.CommandText = "update accounts set balance = balance - 1000 where account_id = '1111'";  
   cmd.ExecuteNonQuery ();
    // Credit $1,000 to account 2222   
  cmd.CommandText = "update accounts set balance = " +         "balance + 1000 where account_id = '2222'";  
   cmd.ExecuteNonQuery ();  
   // Commit the transaction (commit changes)  
   trans.Commit (); }
catch (SqlException) {     // Abort the transaction (roll back changes)  if (trans != null) trans.Rollback (); }
finally {     conn.Close (); }

30. Parameterized Commands Example
SqlConnection conn = new SqlConnection ("server=localhost;database=mybank;uid=sa;pwd="); try { conn.Open (); // Create and initialize a SqlCommand object SqlCommand cmd = new SqlCommand("update accounts set balance = balance " + "where account_id conn); cmd.Parameters.Add SqlDbType.Money); cmd.Parameters.Add SqlDbType.Char); // Debit $1,000 from account 1111 = -1000; = "1111"; cmd.ExecuteNonQuery (); // Credit $1,000 to account 2222 = 1000; = "2222"; cmd.ExecuteNonQuery (); } catch (SqlException ex) { // TODO: Handle the exception } finally { conn.Close (); }

31. Programming Microsoft .Net by Jeff Prosise
References
ADO.Net by Alex Homer
Programming Microsoft .Net by Jeff Prosise

32. Thank you