ParentDataRelation Class

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Establishes query-based master-detail relation.

Syntax

Visual Basic
C#


'Declaration Public Class ParentDataRelation


public class ParentDataRelation

Remarks

The ParentDataRelation class is designed to establish a master-detail relationship where details data is not cached on the client. Every time the current position in the master table is changed, the client DbDataTable requests the appropriate portion of data from the server.

Use property ParentTable to specify master DbDataTable, and the properties ParentColumnNames and ChildColumnNames to describe the relationiship.

Note that this feature can be used only for two instances of DbDataTable class that have same DbDataTable.Owner. In other words, the DbDataTable objects must reside on the same forms.

Example

The following example shows how to render related data in two grids.

csharp


SqlConnection connection = new SqlConnection( "User Id=sa;Server=localhost;Initial Catalog=Test;"); connection.Open(); SqlDataTable deptTable = new SqlDataTable("SELECT * FROM dept", connection); SqlDataTable empTable = new SqlDataTable("SELECT * FROM emp", connection); empTable.ParentRelation.ParentTable = deptTable; empTable.ParentRelation.ParentColumnNames = new string[] { "deptno" }; empTable.ParentRelation.ChildColumnNames = new string[] { "deptno" }; deptTable.Owner = this; empTable.Owner = this; deptTable.FetchAll = true; empTable.FetchAll = true; deptTable.Open(); empTable.Open(); deptDataGrid.DataSource = deptTable; empDataGrid.DataSource = empTable;

SqlConnection connection = new SqlConnection(
    "User Id=sa;Server=localhost;Initial Catalog=Test;");
connection.Open();
SqlDataTable deptTable = new SqlDataTable("SELECT * FROM dept", connection);
SqlDataTable empTable = new SqlDataTable("SELECT * FROM emp", connection);
empTable.ParentRelation.ParentTable = deptTable;
empTable.ParentRelation.ParentColumnNames = new string[] { "deptno" };
empTable.ParentRelation.ChildColumnNames = new string[] { "deptno" };
deptTable.Owner = this;
empTable.Owner = this;
deptTable.FetchAll = true;
empTable.FetchAll = true;
deptTable.Open();
empTable.Open();
deptDataGrid.DataSource = deptTable;
empDataGrid.DataSource = empTable;

Visual Basic


Dim connection As New SqlConnection( _ "User Id=sa;Server=localhost;Initial Catalog=Test;") connection.Open() Dim deptTable As New SqlDataTable("SELECT * FROM dept", connection) Dim empTable As New SqlDataTable("SELECT * FROM emp", connection) empTable.ParentRelation.ParentTable = deptTable empTable.ParentRelation.ParentColumnNames = New String() {"deptno"} empTable.ParentRelation.ChildColumnNames = New String() {"deptno"} deptTable.Owner = Me empTable.Owner = Me deptTable.FetchAll = True empTable.FetchAll = True deptTable.Open() empTable.Open() deptDataGrid.DataSource = deptTable empDataGrid.DataSource = empTable

Dim connection As New SqlConnection( _
    "User Id=sa;Server=localhost;Initial Catalog=Test;")
connection.Open()
Dim deptTable As New SqlDataTable("SELECT * FROM dept", connection)
Dim empTable As New SqlDataTable("SELECT * FROM emp", connection)
empTable.ParentRelation.ParentTable = deptTable
empTable.ParentRelation.ParentColumnNames = New String() {"deptno"}
empTable.ParentRelation.ChildColumnNames = New String() {"deptno"}
deptTable.Owner = Me
empTable.Owner = Me
deptTable.FetchAll = True
empTable.FetchAll = True
deptTable.Open()
empTable.Open()
deptDataGrid.DataSource = deptTable
empDataGrid.DataSource = empTable

Inheritance Hierarchy

System.Object
Devart.Common.ParentDataRelation

Reference

ParentDataRelation Members
Devart.Common Namespace

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