Tables Relationships

DataManager supports defining relationships between tables.

A relationship connects a field in one table to a field in another table.

After a relationship is created, fields from the related table can be accessed using the relationship name.

Relationships are defined at the DataManager level.

Creating a Relationship

Use addRelationship to define a relationship between two tables.

dataManager.addRelationship(
  sourceTable,
  sourceFieldName,
  sourceRelationshipName,
  targetTable,
  targetFieldName,
  targetRelationshipName
);

Parameters

• sourceTable - The table where the relationship is defined.

• sourceFieldName - The field in the source table used for matching.

• sourceRelationshipName - The name used to access the related table from the source table.

• targetTable - The related table.

• targetFieldName - The field in the target table used for matching.

• targetRelationshipName - The name used to access the source table from the target table.

The method returns an IRelationship object describing the relationship.

Example

const dataManager = spread.dataManager();

const orders = dataManager.addTable("orders", {
  data: [
    { orderId: 1, orderDate: "2024-01-01", employeeId: 100 },
    { orderId: 2, orderDate: "2024-01-02", employeeId: 101 }
  ]
});

const employees = dataManager.addTable("employees", {
  data: [
    { employeeId: 100, firstName: "Nancy", title: "Manager", address: "Seattle" },
    { employeeId: 101, firstName: "Andrew", title: "Sales", address: "Tacoma" }
  ]
});

// Create relationship
const relationship = dataManager.addRelationship(
  orders,
  "employeeId",
  "employee",
  employees,
  "employeeId",
  "orders"
);

// Access related fields in a view
const myView = orders.addView("myView", [
  { value: "orderId" },
  { value: "orderDate" },
  { value: "employee.firstName" },
  { value: "employee.title" },
  { value: "employee.address" }
]);

In this example:

• "employee" is the relationship name defined on the orders table.

• Related table fields are accessed using dot notation:

relationshipName.fieldName

Accessing Related Data

After a relationship is created, related fields can be referenced in a View using:

relationshipName.fieldName

Example:

{ value: "employee.firstName" }

The relationship name acts as a navigation path to the related table.

Relationship Storage

Relationships are stored in the DataManager.

Each call to addRelationship creates a new relationship entry.

Multiple relationships can coexist within the same DataManager.

Relationship names are defined by the developer. The API does not enforce uniqueness of relationship names.

Removing a Relationship

Use removeRelationship to remove a relationship by name:

dataManager.removeRelationship("employee");

After removal, related field access through that relationship name is no longer available.