Session x(ado.net)
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ADO.NET is a set of .NET classes that allows retrieving, manipulating, and updating data from various sources. It consists of two main components - the dataset, which stores disconnected data, and data providers that connect to data sources using connections, commands, data readers, and data adapters. Data providers exist for SQL Server, OLE DB, and ODBC sources and each consists of classes to connect, execute commands, populate datasets, and update data sources.
Session x(ado.net)
- 1. Overview of ADO.NET Architecture of ADO.NET .NET Data Providers Data Providers Components
- 2. ADO.NET is a large set of .NET classes that enable us to retrieve and manipulate data, and update data. As an integral part of the .NET framework, it shares many of its features: sources, in very many different ways.
- 3. features such as multi-language support, garbage collection, just-in-time compilation, object-oriented design, and dynamic caching, and is far more than an upgrade of previous versions of ADO.
- 4. The ADO.NET object model consists of two fundamental components: the Dataset, which is disconnected from the data source and doesn't need to know where the data it holds came from; and the .NET data provider. The .NET data providers allow us to connect to the data source, and to execute SQL.
- 5. At the time of writing, there are three .NET data providers available: for SQL Server, for OLE DB data sources. for ODBC-compliant data sources. Each provider exists in a namespace within the System. Data namespace, and consists of a number of classes.
- 6. Each .NET data provider consists of four main components: Connection – used to connect to the data source Command– used to execute a command against the data source and retrieve a Data Reader.
- 7. Dataset, or to execute an INSERT, UPDATE, or DELETE command against the data source Data Reader– a forward-only, read-only connected result set. Data Adapter – used to populate a Dataset with data from the data source, and to update the data source
- 9. The connection classes are very similar to the ADO Connection object, and like that, they are used to represent a connection to a specific data source. The connection classes store the information that ADO.NET needs to connect to a data source in the form of a familiar connection string (just as in ADO).
- 10. The command classes expose the IDbCommand interface and are similar to the ADO Command object – they are used to execute SQL statements or stored procedures in the data source. Also, like the ADO Command object, the command classes have a Command Text property, which contains the text of the command to be
- 11. executed against the data source, and a Command Type property, which indicates whether the command is a SQL statement, the name of a stored procedure, or the name of a table.
- 13. The DataReader is ADO.NET's answer to the connected recordset in ADO. However, the DataReader is forward-only and read-only – we can't navigate through it at random, and we can't use it to update the data source. It
- 14. therefore allows extremely fast access to data that we just want to iterate through once, and it is recommended to use the Data Reader (rather than the DataSet) wherever possible.
- 16. The other major component of ADO.NET is the DataSet; this corresponds very roughly to the ADO recordset. It differs, however, in two important respects. The first of these is that the DataSet is always
- 17. exactly the same way to manipulate data from a traditional data source or from an XML document. In order to connect a DataSet to a data source, we need to use the DataAdapter as an intermediary between the DataSet and the .NET data provider: