Creating Single- and Multi-Column Primary Keys : DataTable « ADO.Net « C# / CSharp Tutorial






using System;
using System.Data;

    class Program
    {
        static void Main(string[] args)
        {
            DataTable dt1 = new DataTable("Table-1");
            DataColumn pkCol = dt1.Columns.Add("Id", typeof(int));
            dt1.Columns.Add("Field1", typeof(string)).MaxLength = 50;
            dt1.PrimaryKey = new DataColumn[] { pkCol };

            DataTable dt2 = new DataTable("Table-2");
            dt2.Columns.Add("Id", typeof(int));
            dt2.Columns.Add("Field1", typeof(string)).MaxLength = 50;
            UniqueConstraint uc = new UniqueConstraint("PrimaryKey-2", dt2.Columns["Id"], true);
            dt2.Constraints.Add(uc);

            DataTable dt3 = new DataTable("Table-3");
            dt3.Columns.Add("Id1", typeof(int));
            dt3.Columns.Add("Id2", typeof(int));
            dt3.Columns.Add("Field1", typeof(string)).MaxLength = 50;
            dt3.Constraints.Add("PrimaryKey-3",new DataColumn[] { dt3.Columns["Id1"], dt3.Columns["Id2"] },true);

        }
    }








32.36.DataTable
32.36.1.Loop through DataTable by DataRow
32.36.2.Use DataTable to insert a Row
32.36.3.Add Row to DataTable
32.36.4.Accessing Data Values in a DataTable or DataSet
32.36.5.Adding Columns to DataTable
32.36.6.Adding Constraint to DataTable
32.36.7.Adding a Calculated Column to a DataTable
32.36.8.Adding a Column to a Child DataTable That Displays Data from the Parent Table
32.36.9.Adding a Column to a Parent DataTable That Aggregates a Child Table's Column Values
32.36.10.Creating a DataColumn and Adding It to a DataTable
32.36.11.Creating a DataTable and Adding It to a DataSet
32.36.12.Retrieving a Result Set Using a DataTable or a DataSet
32.36.13.Pop DataTable
32.36.14.Output Constraint Properties
32.36.15.Output the rows from the DataTable with foreach loop over DataRowCollection
32.36.16.Modify DataTable
32.36.17.Loop through the rows in DataTable
32.36.18.Creating Single- and Multi-Column Primary Keys
32.36.19.Creating a Unique Constraint
32.36.20.Append columns to DataTable
32.36.21.Accessing FirstName value in row 3 directly
32.36.22.Filter Sort
32.36.23.Retrieves a schema table for a query