Overview of ADO.NETwith the .NET Framework

Scalable Development, Inc.Building systems today that perform tomorrow.

.NET Experiences

PDC 2000 Build (July 2000). Visual Studio 1.0 Beta 1 (November 2000). Book began (January 2001). Visual Studio 1.0 Beta 2 (June 2001). First Production ASP.NET App (July 2001). Production Windows Service (November 2001).

Runs today. 4 Production Applications by shipment. Multiple running applications.

.NET Resources

ASP.NET – www.asp.net AspAdvice – www.aspadvice.com Windows Forms – www.windowsforms.net Architecture –

msdn.microsoft.com/architecture .NET News – www.dotnetwire.com

Agenda

Design PhilosophyArchitectural OverviewFeaturesWhen to use What (Code Examples)Summary

Design Philosophy Unified Data Story (data, xml, cache objects)

Data is Data; object model is choice XML objects feel like XML, Data objects feel like Data,

Typed Objects feel like objects Factored components

Explicit model; no black boxes! (Customers/helper code wires together components)

Predictable behaviour, semantics Optimized performance

Disconnected Relational DataSet Get Data as fast as possible

Managed Data Overview

What Happenedto My RecordSet?

RecordSet Updateable? Scrollable? Bookmarks? Rowcount?

Holding server resources? Cache on client?

DataReader Connected, non-cached, FO/RO RecordSet

DataSet Disconnected, cached, scrollable data

DataAdapter Logic for populating the DataSet and propagating

changes back to the datasource

Managed Providers Manages interaction to a data source

Managed equivalent of OLE DB layer Directly exposes consumer interfaces Not a full featured data store interface Specific to (Optimized for) DataSource

Managed Provider Object Model Connection

Like ADODB.Connection Command

Like ADODB.Command DataReader

Similar to FO/RO ADODB.RecordSet Fields accessed through strongly typed, indexed accessors

Database Support

System.Data.SQLClient SQL Server 7 SQL Server 2000

Oracle.DataAccess (ODP.NET). System.Data.Oracle (MS). DB2 (only supports .NET 1.0). MySql. System.Data.OleDb System.Data.Odbc ODBC drivers.

Oracle Managed Providers

Microsoft. No support for COM+.

Oracle. Requires Oracle 9iR2 client.

Oracle Support Through OleDb

Microsoft Driver for Oracle. (MsDaOra)7.x datatypes.No 8.x datatypes.

Oracle OleDb Driver. (OraOleDb.Oracle)7.x datatypes.8.x datatypes.9.x datatypes.COM+ challenged.

Oracle Support Through ODBC

Microsoft Driver for Oracle.

Oracle ODBC driver.Thread challenged.

Oracle Gotchas

Use the latest Oracle SQL Net.

Don’t use COM+ transactions, unless youneed them. Info - Oracle is working on an OleDb driver that supports COM+transactions better.

Always close connections!!!!!!

DataSet Common client data store

Relational View of Data Tables, Columns,

Rows, Constraints, Relations

Directly create metadata and insert data

DataSetDataSetTablesTables

TableTable

ColumnsColumnsColumnColumn

ConstraintsConstraintsConstraintConstraint

RowsRowsRowRow

RelationsRelationsRelationRelation

DataSet Common client data store

Explicit Disconnected Model Disconnected, remotable object No knowledge of data source or properties

Common BehaviourPredictable performance characteristics

Strong Typing 3-D Collection What to return from a DAL. Uses DataReader underneath the covers. Some column metadata is not available.

Data Adapter Loads a table from a data store and

writes changes back. Exposes two important methods:

Fill(DataSet,DataTable)Update(DataSet,DataTable)

Provides mappings between tables & columns User provides insert/update/delete commands

Allows use of Stored ProceduresCommandBuilder component available (not

used much in ASP.NET) Allows single DataSet to be populated from multiple

different datasources

ADO.NET and XML

The DataSet Loads/saves XML data into/out of DataSet Schema can be loaded/saved as XSD Schema can be inferred from XML Data

The DataSet can be associated with an XmlDataDocument Exposes a relational view over structured XML

According to the DataSet schema Allows strong typing, control binding, relational access of

XML data Allows XML tools (schema validation, XSL/T, XPath queries)

against relational data Preserves full fidelity of XML Document

When to use What Connected Data Access

Code Examples:Retrieving ResultsInsert, Update, and

Delete. Disconnected Data Access

Code Examples:Application DataLoading XMLClient Cursor Updating

XML View of Relational Data Code Example:

SQLXMLXML Manipulations

Connected Data Access Connected Data Access - Managed Providers

Connection, TransactionConnecting to DataSourceStarting/Ending Transactions

Command, ParametersDatabase Updates, Selects, DDL

DataReader(FO/RO) Server Cursor

DataAdapterPushing data into DatasetReading changes out of DataSet

Code: Retrieving Results

‘Create and open an OleDbConnectionDim OleDbCn as new OleDbConnection(“……”)OleDbCn.Open()

‘Create and execute OleDbCommandDim OleDbCmd as new OleDbCommand("Select * from authors where ...", OleDbCn)Dim dr as DataReaderdr = OleDbCmd.ExecuteReader()

‘Retrieve Resultswhile(dr.Read())

Console.WriteLine("Name = " + dr("au_lname“))End whiledr.Close()OleDbCn.Close() ‘This is VERY IMPORTANT

Disconnected Data Access

Disconnected Data Access - DataSet Application Data Remoting Results

SOAP, WebMethods, Remoting Caching Results

ASP.NET Cache Persisting results

Save Data as XML, Schema as XSD User interaction

Scrolling, sorting, filtering DataView, DataViewManager

Binding Windows controls

Code: Application Data

‘ Create an "Inventory" TableDim ds as new DataSet() Dim inventory as new DataTable("Inventory")inventory.Columns.Add("TitleID",typeof(Int32))inventory.Columns.Add("Quantity",typeof(Int32))ds.Tables.Add(inventory)

‘ Add a record to the Inventory tableDim row as inventory.NewRow()Row("TitleID“)=1Row("Quantity“)=25inventory.Rows.Add(row)

Code: Loading XML

‘Load DataSet with XMLDim ds as new DataSet()ds.ReadXml("inventory.xml")

‘Add a record to the Inventory tableDim inventory as new DataTable = ds.Tables("Inventory“)Dim row as DataRow = inventory.NewRow()Row("TitleID“)=1Row("Quantity“)=25inventory.Rows.Add(row)

‘Write out XMLds.WriteXml("updatedinventory.xml")

Code: Insert/Update/Delete

Dim OleDbCn as new OleDbConnection(“…….”)Dim OleDbCM as new OleDbCommand(

“Insert/Update/Delete Command“, OleDbCn)OleDbCn.Open()OleDbCm.ExecuteNonQuery()If OleDbCn.State <> ConnectionState.StateClosed then

OleDbCn.Close()End ifOleDbCn = Nothing ‘Old habits die hard

Code: Client Cursor Updating (easy)

‘Populate DataSetDim OleDbDA as new OleDbDataAdapter(

"Select * from customers“, OleDbCn);Dim ds as new Dataset() OleDbDA.MissingSchemaAction = MissingSchemaAction.AddWithKeyOleDbDA.Fill(ds, "Customer")

‘Find customer w/PK value of 256Dim dr as DataRow = ds.Tables("Customer“).Rows.Find(256)

‘Change LastNameDr("LastName“) = "Smith"

‘Update DataBaseDim OleDbCb as new OleDbCommandBuilder = OleDbCommandBuilder(da)OleDbDa.Update(ds, "Customer")

Code: Client Cursor Operations (harder)

‘Populate DataSetDim OleDbDA as new OleDbDataAdapter("Select customerId, customerName from customers“, OleDbCn);Dim ds as new Dataset() Dim dr as DataRow

OleDbDA.Fill(ds, "Customer")

OleDbDA.InsertCommand = new OleDbCommand(“insert into customers (CustomerName) values (@CustomerName)”, OleDbCn)

dr = ds.Tables(“Customer”).NewRow()‘Add Customer NameDr("Customer Name“) = "Fred's Company"

‘Update DataBaseds.Tables(“Customer”).Rows.Add(dr)OleDbDA.Update(ds, “Customer”)

Notes on the Client Cursor Update

Individual commands are sent.

Can be wrapped in a transaction.

CommandBuilder is “relatively” inefficient.

Code: Manual Transaction

Dim OleDbCM as new OleDbCommand(“Insert/Update/Delete Command“, OleDbCn)

Dim OleDbTx as OleDbTransactionOleDbTx = OleDbCn.BeginTransaction(Isolation.ReadUncommitted)OleDbCm.Transaction = OleDbTxTry

OleDbCn.Open()OleDbCm.ExecuteNonQuery()OleDbTx.Commit()

Catch exc as ExceptionOleDbTx.RollBack()Throw( new Exception( “Error Occurred”, exc.InnerException )

FinallyIf OleDbCn.State <> ConnectionState.StateClosed then

OleDbCn.Close()End ifEnd TryOleDbCn = Nothing

Cleanup

Close your connection objects and return them to the connection pool.

Dispose all objects. Don't wait on the finalizer.

Great, Now What’s Missing?

Server-side scrollable cursor support. (not an issue for Oracle)

Complete column information.

ADOX.Catalog type of support. No support for creating tables, columns, users, indexes, ……..

ADO Classic in .NET

Works.Can continue to use it.Required for ADOX support.

Summary

ADO.NET is… Optimized for Data Access.

Managed Providers for connected access

DataSet for disconnected, user interaction

DataReader for connected RO use. Open Architecture

No Black Boxes Tightly Integrated with XML

DataSet reads/writes XMLXmlDataDocument integrates relational

and XML views

Questions?

Scalable Development, Inc. Consulting & Development Services. http://www.scalabledevelopment.com 865-693-3004. wallym@scalabledevelopment.com

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Scalable Development, Inc.Building systems today that perform tomorrow.