DataTable Class

The System.Data.DataTable class represents an in‑memory table of data. It is part of the System.Data namespace and is used extensively with DataSet, DataAdapter, and other ADO.NET components.

Namespace

System.Data

Assembly

System.Data.dll

Key Properties

Name	Type	Description
TableName	string	Gets or sets the name of the table.
Columns	DataColumnCollection	Collection of columns that define the schema.
Rows	DataRowCollection	Collection of rows containing the data.
PrimaryKey	DataColumn[]	Array of columns that act as the primary key.
Constraints	ConstraintCollection	Constraints such as primary key and foreign key constraints.

Common Methods

public void AcceptChanges();
public DataRow NewRow();
public void Load(IDataReader reader);
public DataRow Find(object[] keyValues);
public void Clear();

using System;
using System.Data;

class Example
{
    static void Main()
    {
        // Create a DataTable with two columns.
        DataTable table = new DataTable("Employees");
        table.Columns.Add("Id", typeof(int));
        table.Columns.Add("Name", typeof(string));

        // Define primary key.
        table.PrimaryKey = new[] { table.Columns["Id"] };

        // Add rows.
        table.Rows.Add(1, "Alice");
        table.Rows.Add(2, "Bob");

        // Find a row by primary key.
        DataRow row = table.Rows.Find(1);
        Console.WriteLine($\"Found: {row["Name"]}\");
    }
}

Example: Loading Data from a Database

using System;
using System.Data;
using System.Data.SqlClient;

class LoadDemo
{
    static void Main()
    {
        string connStr = "Data Source=.;Initial Catalog=Northwind;Integrated Security=True";
        using (SqlConnection conn = new SqlConnection(connStr))
        {
            conn.Open();
            SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM Customers", conn);
            DataTable customers = new DataTable();
            adapter.Fill(customers);

            foreach (DataRow r in customers.Rows)
                Console.WriteLine($"{r["CustomerID"]} - {r["CompanyName"]}");
        }
    }
}