Json Relationship

install via npm i json-relationship

This is a basic json relationship implementation following the minimal specification. A json relationship is established by

    var Relationship = require("json-library").relation.Relationship;
    var relation = new Relationship(data, relationshipDefinition);

The main function of a relationship is to

• load one or all related tupels specified in foreign keys or pivot table to its parent tupel
• update the pivot table or foreign keys of one or all tupels
• unload reverse one or all established relations

A relationship instance also includes helpers to

• loadAll, updateAll and unloadAll relationships
• link a new object to a tupel and
• unlink the given object from a tupel

Usage

The following example

    var Relationship = require("json-library").relation.Relationship;
 
    var relation = new Relationship(data, "parent has_one:child through:parent_children as:workload");
    relation.loadAll();

will change the json object

    {
        parent: {
            p_01: {},
            p_02: {},
        },
        child: {
            c_01: {id: "c_01"},
            c_02: {id: "c_02"}
        },
        parent_children: {
            p_01: ["c_02", "c_01"],
            p_01: ["c_01"]
        }
    }

to

    {
        parent: {
            p_01: {
                workload: [
                    {id: "c_02"},
                    {id: "c_01"}
                ]
            },
            p_02: {
                workload: [
                    {id: "c_01"}
                ]
            }
        ...

For further details and examples check createDefinitionObject and the unit tests

Relationship Definition

A relationship object may be also created by: "[model] [[type]:[related] [mapping]:[path] (as:[alias])]". Using createDefinitionObject(string) a valid relationship Object is retrieved. For details see createDefinitionObject