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DataTables (ADO.NET)

A DataSet is made up of a collection of tables, relationships, and constraints. In ADO.NET, DataTable objects are used to represent the tables in a DataSet. A DataTable represents one table of in-memory relational data; the data is local to the .NET-based application in which it resides, but can be populated from a data source such as Microsoft SQL Server using a DataAdapter For more information, see Populating a DataSet from a DataAdapter (ADO.NET).

The DataTable class is a member of the System.Data namespace within the .NET Framework class library. You can create and use a DataTable independently or as a member of a DataSet, and DataTable objects can also be used in conjunction with other .NET Framework objects, including the DataView. You access the collection of tables in a DataSet through the Tables property of the DataSet object.

The schema, or structure of a table is represented by columns and constraints. You define the schema of a DataTable using DataColumn objects as well as ForeignKeyConstraint and UniqueConstraint objects. The columns in a table can map to columns in a data source, contain calculated values from expressions, automatically increment their values, or contain primary key values.

In addition to a schema, a DataTable must also have rows to contain and order data. The DataRow class represents the actual data contained in a table. You use the DataRow and its properties and methods to retrieve, evaluate, and manipulate the data in a table. As you access and change the data within a row, the DataRow object maintains both its current and original state.

You can create parent-child relationships between tables using one or more related columns in the tables. You create a relationship between DataTable objects using a DataRelation. DataRelation objects can then be used to return the related child or parent rows of a particular row. For more information, see Adding DataRelations (ADO.NET).

In This Section

  • ADO.NET
    Describes the ADO.NET architecture and components, and how to use them to access existing data sources and manage application data.

  • DataSets, DataTables, and DataViews (ADO.NET)
    Provides information about the ADO.NET DataSet including how to create relationships between tables.

  • Constraint Class
    Provides reference information about the Constraint object.

  • DataColumn Class
    Provides reference information about the DataColumn object.

  • DataSet Class
    Provides reference information about the DataSet object.

  • DataTable Class
    Provides reference information about the DataTable object.

  • .NET Framework Class Library Overview
    Provides an overview of the .NET Framework class library, including the System namespace as well as its second-level namespace, System.Data.

See Also

Other Resources

ADO.NET Managed Providers and DataSet Developer Center