1. 04 | Data Acess Technologies
Bruno Terkaly | Technical Evangelist
Bret Stateham | Technical Evangelist

2. Module Overview ADO.NET LINQ (Language Integrated Query)
XML (Extensible Markup Language)
LINQ to XML

3. ADO.NET

4. Basic ADO.NET Objects Connection* DataReader*
Command* (SELECT, …)
Results
string constr = "Server=server;Database=db;User ID=user;Password=pwd;...";
using(SqlConnection connection = new SqlConnection(constr)) {
string query = "SELECT TOP 10 PositionID, ReportedAt, Latitude, Longitude FROM dbo.Positions;";
using (SqlCommand cmd = new SqlCommand(query,connection)) {
connection.Open();
using (SqlDataReader rdr = command.ExecuteReader())
while(rdr.Read())
string position =
string.Format("{0},{1},{2},{3}",rdr.GetInt32(0),rdr.GetDateTime(1),rdr.GetFloat(2),rdr.GetFloat(3));
Console.WriteLine(position); }
* ADO.NET Provider Specific: SqlConnection, SqlCommand, SqlDataReader

5. ADO.NET Providers

6. DataTable and DataAdapter
Connection*
DataTable
DataAdapter*
Fill()
SelectCommand*
Update()
InsertCommand*
UpdateCommand*
DeleteCommand*
* ADO.NET Provider Specific: SqlConnection, SqlCommand, SqlDataAdapter

7. DataSets Connection* DataSet DataAdapter(s)*
Commands*
Fill/Update
* ADO.NET Provider Specific: SqlConnection, SqlCommand, SqlDataAdapter

8. Querying data with ADO.NET

9. LINQ (Language-INtegrated Query)

10. Data Sources & Client Access
Relational DBs
XML
Collections
ADO.NET / SQL
DOM / XPath C#

11. LINQ to Objects & IEnumerable
LINQ to the Rescue!
Relational DBs
XML
Collections
LINQ
LINQ to Entities
& IQueryable
LINQ to XML
LINQ to Objects & IEnumerable C#

12. What is LINQ? A way to query data in memory
A collection of extension methods to IEnumerable
Queries are “composable” and don’t execute until data is accessed.
Allows querying, filtering, aggregating, joining, collections in memory
A way to ship queries across application layers
IQueryable represents the intention of the query
Can be shipped between application tiers (service <> client)
Service can provide the initial query
Client can further “compose” the query (filter, sort, etc)
Client passes the composed query back to the service
The service returns the data as specified by the query. Cool!

13. LINQ to Objects

14. XML (Extensible Markup Language)

15. Good Old XML Read all about it: www.w3.org/xml (seriously)
<Positions>
<Position PositionID="1">
<ReportedAt> T22:51:00</ReportedAt>
<Region>North Carolina</Region>
<Country>United States</Country>
<Latitude> </Latitude>
<Longitude> </Longitude>
</Position>
<Position PositionID="2">
<ReportedAt> T22:54:00</ReportedAt>
<Latitude> </Latitude>
<Longitude> </Longitude>
<Position PositionID="3">
<ReportedAt> T17:17:00</ReportedAt>
<Latitude> </Latitude>
<! >
</Positions>
Read all about it: (seriously)
Family of related standards
XML
XML Schemas
XPath
XQuery
XSLT (Transformations)
XSL-FO …

16. Working with XML in Code
System.Xml
XmlDocument for Document Object Model (DOM) based operations
XmlReader for SAX (streaming) based operations
Create XML with XmlDocument, XmlElement, XmlAttribute…
Can save / load XML from files
Can parse XML from strings

17. System.Xml Namespace XmlDocument XmlDeclaration XmlComment XmlElement
<?xml version="1.0" ?>
<!– Sample Position -->
<Position>…</Position>
<Position
PositionID="1">
<Latitude>
</Latitude>
<Longitude>
</Longitude>
</Position>
</Positions>
XmlDocument
XmlDeclaration
XmlComment
XmlElement
XmlAttribute
XmlText
XmlNode

18. DOM Based XML Processing

19. LINQ to XML

20. LINQ to Objects & IEnumerable
LINQ to the Rescue!
Relational DBs
XML
Collections
LINQ
LINQ to Entities
& IQueryable
LINQ to XML
LINQ to Objects & IEnumerable C#

21. System.Xml.Linq Namespace
XDocument
<?xml version="1.0" ?>
<!– Sample Position -->
<Position>…</Position>
<Position
PositionID="1">
<Latitude>
</Latitude>
<Longitude>
</Longitude>
</Position>
</Positions>
XDeclaration
XComment
XElement
XAttribute
XText

22. LINQ to XML