Build Your Own ASP.NET 2.0 Web Site Using C# & VB, Second Edition

What is a Data Set Made From?

A data set comprises many parts, all of which are required for its usage. The fol-

lowing classes will be introduced and discussed in this section:

❑

DataSet

❑

SqlDataAdapter

❑

DataTable

❑

DataColumn

❑

DataRow

❑

DataRelation

❑

DataView

We need to use most of these classes in order to work with data sets. For instance,

the SqlDataAdapter class acts as the communication point between the DataSet

and the database. The data adapter knows how to fill a DataSet with data from

the data source; it also knows how to submit to the data source any changes

you’ve made to a DataSet.

Data Adapters

Of all these objects, only SqlDataAdapter depends on a particular data

provider, and as such, it is interchangeable with other classes that work with

data providers, including OracleDataAdapter, OleDbDataAdapter, and

so on. As this class is the bridge between the database and your local data

storage objects (the other classes mentioned), it makes sense for the class to

be database-specific. The DataSet, DataTable, and other classes, store the

data locally and don’t need to be aware of the source of that data.

A DataSet will always contain at least one DataTable, but it can contain many.

These DataTables contain DataColumns and DataRows. If we needed to establish

a relationship between multiple DataTables within a DataSet, we’d use

DataRelations. Finally, we’d create DataViews to query the DataSet.

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What is a Data Set Made From?