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


MongoDBConnection connection = new MongoDBConnection( "Host=localhost;Port=27017;Database=sample;User Id=user;Password=pwd;"); connection.Open(); MongoDBDataTable deptTable = new MongoDBDataTable("SELECT * FROM dept", connection); MongoDBDataTable empTable = new MongoDBDataTable("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;

MongoDBConnection connection = new MongoDBConnection(
    "Host=localhost;Port=27017;Database=sample;User Id=user;Password=pwd;");
connection.Open();
MongoDBDataTable deptTable = new MongoDBDataTable("SELECT * FROM dept", connection);
MongoDBDataTable empTable = new MongoDBDataTable("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 MongoDBConnection( _ "Host=localhost;Port=27017;Database=sample;User Id=user;Password=pwd;") connection.Open() Dim deptTable As New MongoDBDataTable("SELECT * FROM dept", connection) Dim empTable As New MongoDBDataTable("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 MongoDBConnection( _
    "Host=localhost;Port=27017;Database=sample;User Id=user;Password=pwd;")
connection.Open()
Dim deptTable As New MongoDBDataTable("SELECT * FROM dept", connection)
Dim empTable As New MongoDBDataTable("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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