Using Microsoft .NET and C# with Oracle 9i - Creating a DataSet from and Oracle Database
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The first step to creating a DataSet from an Oracle database is to make use of a new secondary class, called the OracleDataAdapter. This class basically takes the data as it comes back from Oracle and parses it into a .NET DataSet. Another useful characteristic of this class is that it takes the place of an OracleCommand object. The OracleDataAdapter contains the command string and parameter objects required to execute a command (either text or stored procedure) on the database. There are several ways to create an OracleDataAdapter object. However, the one shown below uses an OracleConnection object and a string to become the Select command.
OracleDataAdapter adapter = new OracleDataAdapter(conn, “select * from users”);
DataSet set = new DataSet();
adapter.fill(set, “users”);
After creating the OracleDataAdapter we create a DataSet object to take the results of the select statement. Then, we use the fill method to populate a DataTable object named “users” inside the DataSet with the data returned from the select statement. Now, you can do all the fun, nifty things you could always do with a DataSet, such as binding it to data driven controls, modifying the data and putting it back into the database. The OracleDataAdapter also contains data members to hold insert, update, and delete commands, so the object can even automate maintaining data in the database in the same state as the DataSet in memory. However, those functions are beyond the purview of this article.
Final Words
Overall, the ODP.NET class framework follows many of the normal conventions that any database programmer finds in other such frameworks. This makes is relatively easy to learn and pick up on for the experienced database programmer, and even for the novice, the classes are laid out in a logical way that makes understanding each ones function easy.
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