AddRelation Method

Overview

The AddRelation method registers a parent / child relationship in IObservableDataSet.Relations, which are used for:.

• Consistent navigation between parent / child rows (depending on your relation navigation APIs).
• Validation workflows such as EnableRelationIntegrity that detect broken foreign-key-style links during editing.

This method delegates to the underlying POCO IDataSet.AddRelation.

Declaration

/// <summary>
/// Adds relation between parent and child tables in a data set
/// IObservableDataSet interface implementation
/// </summary>
/// <param name="relationName">Relation name</param>
/// <param name="parentTableName">Parent table name</param>
/// <param name="parentColumnName">Parent column name</param>
/// <param name="childTableName">Child table name</param>
/// <param name="childColumnName">Child column name</param>
IDataRelation AddRelation(string relationName, string parentTableName, string parentColumnName, string childTableName, string childColumnName)

/// <summary>
/// Adds relation between parent and child tables in a data set using composite keys
/// IObservableDataSet interface implementation
/// </summary>
/// <param name="relationName">Relation name</param>
/// <param name="parentTableName">Parent table name</param>
/// <param name="parentColumnNames">Parent column names</param>
/// <param name="childTableName">Child table name</param>
/// <param name="childColumnNames">Child column names</param>
public static void AddRelation(string relationName, string parentTableName, IList<string> parentColumnNames, string childTableName, IList<string> childColumnNames)

Namespace and Assembly

Namespace: PocoDataSet.ObservableData
Assembly: PocoDataSet.ObservableData.dll

Usage Example

Simple primary and foreign keys example

// 1. Create observable dataset
IObservableDataSet observableDataSet = new ObservableDataSet();

// 2. Add parent Customer table with Id primary key
IObservableDataTable customerObservableDataTable = observableDataSet.AddNewTable("Customer");
customerObservableDataTable.AddColumn("Id", DataTypeNames.INT32);
customerObservableDataTable.AddColumn("Name", DataTypeNames.STRING);

// 3. Add child Order table with CustomerId foreign key
IObservableDataTable orderObservableDataTable = observableDataSet.AddNewTable("Order");
orderObservableDataTable.AddColumn("Id", DataTypeNames.INT32);
orderObservableDataTable.AddColumn("CustomerId", DataTypeNames.INT32, false, false, true);
orderObservableDataTable.AddColumn("Status", DataTypeNames.STRING);

// 4. Add relation between Customer and Order tables: Customer.Id -> Order.CustomerId
observableDataSet.AddRelation("CustomerOrder", "Customer", "Id", "Order", "CustomerId");

// Insert data
IObservableDataRow customerObservableDataRow = customerObservableDataTable.AddNewRow();
customerObservableDataRow["Id"] = 1;
customerObservableDataRow["Name"] = "Acme";
customerObservableDataTable.AcceptChanges();

IObservableDataRow orderObservableDataRow = orderObservableDataTable.AddNewRow();
orderObservableDataRow["Id"] = 1;
orderObservableDataRow["CustomerId"] = 1;
orderObservableDataRow["Status"] = "Open";
orderObservableDataTable.AcceptChanges();

// Now relation navigation works (see GetChildRows / TryGetParentRow docs).
bool hasRelation = observableDataSet.ContainsRelation("CustomerOrder"); // true

Composite primary and foreign keys example

// 1. Create observable dataset
IObservableDataSet observableDataSet = new ObservableDataSet();

// 2. Add parent Customer table with Code1 and Code2 primary keys
IObservableDataTable customerObservableDataTable = observableDataSet.AddNewTable("Customer");
customerObservableDataTable.AddColumn("Code1", DataTypeNames.STRING, false, true);
customerObservableDataTable.AddColumn("Code2", DataTypeNames.STRING, false, true);
customerObservableDataTable.AddColumn("Name", DataTypeNames.STRING);

// 3. Add child Order table with CustomerCode1 and CustomerCode2 composite foreign key
IObservableDataTable orderObservableDataTable = observableDataSet.AddNewTable("Order");
orderObservableDataTable.AddColumn("Id", DataTypeNames.INT32, false, true);
orderObservableDataTable.AddColumn("CustomerCode1", DataTypeNames.STRING, false, false, true);
orderObservableDataTable.AddColumn("CustomerCode2", DataTypeNames.STRING, false, false, true);
orderObservableDataTable.AddColumn("Status", DataTypeNames.STRING);

// Add relation between Customer and Order tables
// Customer.Code1 -> Order.CustomerCode1
// Customer.Code2 -> Order.CustomerCode2
observableDataSet.AddRelation("CustomerOrder", "Customer", new List<string> { "Code1", "Code2" }, "Order", new List<string> { "CustomerCode1", "CustomerCode2" });

// Insert data
IObservableDataRow customerObservableDataRow = customerObservableDataTable.AddNewRow();
customerObservableDataRow["Code1"] = "Acme";
customerObservableDataRow["Code2"] = "Group";
customerObservableDataRow["Name"] = "Performance";
customerObservableDataTable.AcceptChanges();

IObservableDataRow orderObservableDataRow = orderObservableDataTable.AddNewRow();
orderObservableDataRow["OrderId"] = 1;
orderObservableDataRow["CustomerCode1"] = "Acme";
orderObservableDataRow["CustomerCode2"] = "Group";
orderObservableDataRow["Status"] = "Open";
orderObservableDataTable.AcceptChanges();

// Now relation navigation works (see GetChildRows / TryGetParentRow docs).
bool hasRelation = observableDataSet.ContainsRelation("CustomerOrder"); // true

 

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Business Process Programming in .Net
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