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Overview of Data Access. MIS 324 Professor Sandvig. Overview. ADO.NET overview Data Access Displaying data. ADO.NET Overview. “ Any web application worth writing involves data access .” Stephen Walther ADO.NET ActiveX Data Objects Microsoft’s data access technologies
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Overview of Data Access MIS 324 Professor Sandvig
Overview • ADO.NET overview • Data Access • Displaying data
ADO.NET Overview • “Any web application worth writing involves data access.” Stephen Walther • ADO.NET • ActiveX Data Objects • Microsoft’s data access technologies • Set of classes that provide data access services • Class Library: ADO.NET Overview
ADO.NET Overview • Support for most relational databases • Sql Server • Oracle • MySql • Any ODBC compliant database • Open Database Connectivity standard
.NET Data options • Programmatically • Use connection & command objects • Pass SQL to database • Very flexible approach • Similar to PHP • Entity Framework • VS examines database • Creates classes representing database structure • Query with LINQ (language integrated query) • Intellisense support • Added to .NET 3.5 • Proprietary Microsoft product
Retrieving Data • MIS 324 • Will use programmatic approach • Benefits • Flexible • Uses SQL • Standard OOP programming techniques • MIS 424 • Entity Framework • Fast & convenient
MVC Approach • Separation of duties: • Model • Describes application data • DataRepository class • Sql statements and data access classes • Controller • Handles requests • View • Displays data and forms
Repository • All data access logic • Sql statements • Database classes • Connection • Etc. • Goal: Loose coupling • Different data source affects only repository
ORM – Object Relation Mapper • Maps model to sql parameters • Query results to model
ORM • We use Dapper ORM • Developed by StackOverflow • For its site • “King of ORMs”
Retrieving Data .NET MVC Steps: • Model • Database (Sql Server) • DataRepository • Controller • Views
Example – Repository • See handout: Read Database • Output
Summary • ADO.NET • Classes that handle data access • Provides consistent programming interface to data sources • MVC • Database access handled in DataRepository • Controller calls repository methods • Next: SQL Server Express • Creating databases & using with ASP.NET