Transcript Introduction to ASP.NET

Overview of Data Access
MacDonald Ch. 15
MIS 324
Professor Sandvig
Overview
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ADO.NET overview
Datasets & Datatables
Data Access
Displaying data
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Web Controls
ADO.NET Overview
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“Any web application worth writing involves
data access.”
Stephen Walther
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ADO
 ActiveX Data Objects
 Microsoft’s data access technologies
 Set of classes that provide data access
services
 Class Library System.Data
ADO.NET Overview
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Data sources include:
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relational databases
XML files
Web Services
Text files, etc…
Goal
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loose coupling between data source and application
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minimize dependencies
DataSet & DataTable
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Dataset is object for holding data
Central feature of ADO.NET
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Provides tools for working with data
DataSet is a collection of DataTables
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Relationships between tables
Data Sources:
Web Controls:
Relational database
XML file
Web Service
Text file
etc…
Dataset
(data tables)
List controls
Tabular controls
Navigation controls
DataSet & DataTable
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Provides many capabilities of relational database
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Relationships
Keys
Referential integrity
Dataviews: sort and filtering
Change history
Data stored as XML
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Behind the scenes
.NET Data options
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Programmatically
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Use connection & command objects
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2.
Very flexible approach
Similar to PHP
Data Source Controls
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3.
Pass SQL to database
Drag & drop in Visual Studio
Declarative approach
Easy but inflexible
Added in .NET 2.0
Entity Framework
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Creates objects representing database structure
Query with SQL or Entity SQL
Added to .NET 3.5
Retrieving Data
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MIS 324
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Will use programmatic approach
Benefits
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Flexible
Uses standard OOP programming techniques
MIS 424
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Data Source Controls
Entity Framework
Displaying Data
Steps:
1. Retrieve data from datasource
2. Fill DataTable
3. “Bind” to web control
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b.
c.
List controls (1 column)
Tabular controls (>1 column)
Single record controls
B. Displaying Data
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Bind datatable to web control
Web Controls
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List Controls
Tabular Controls
Single record controls
Example: source, output
Summary
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ADO.NET
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Dataset
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Memory resident data container
Bind to Web Controls
Web Controls
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Classes that handle data access
Provides consistent programming interface to data
sources
Write HTML & data to client
Next: SQL Server Express
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Creating databases & using with ASP.NET