entity.diff( )

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4D v17.4

entity.diff( )

Description

The entity.diff( ) method compares the contents of two entities and returns their differences.

In entityToCompare, pass the entity to be compared to the original entity.

In attributesToCompare, you can designate specific attributes to compare. If provided, the comparison is done only on the specified attributes. If not provided, all differences between the entities are returned.

The differences are returned as a collection of objects whose properties are:

Property name	Type	Description
attributeName	String	Name of the attribute
value	Depends on attribute type	Value of the attribute in the entity
otherValue	Depends on attribute type	Value of the attribute in entityToCompare

Only attributes with different values are included in the collection. If no differences are found, entity.diff( ) returns an empty collection.

The method applies for properties whose kind is storage or relatedEntity (see dataClassAttribute.kind). In case a related entity has been updated (meaning the foreign key), the name of the related entity and its primary key name are returned as attributeName properties (value and otherValue are empty for the related entity name)

If one of the compared entities is Null, an error is raised.

Example 1

 C_COLLECTION($diff1;$diff2)

 employee:=ds.Employee.query("ID=1001").first()

 $clone:=employee.clone()

 employee.firstName:="MARIE"

 employee.lastName:="SOPHIE"

 employee.salary:=500

 $diff1:=$clone.diff(employee) // All differences are returned

 $diff2:=$clone.diff(employee;New collection"firstName";"lastName"))

  // Only differences on firstName and lastName are returned

$diff1:

[
    {
        "attributeName": "firstName",
        "value": "Natasha",
        "otherValue": "MARIE"
    },
    {
        "attributeName": "lastName",
        "value": "Locke",
        "otherValue": "SOPHIE"
    },
    {
        "attributeName": "salary",
        "value": 66600,
        "otherValue": 500
    }
]

$diff2:

[
    {
        "attributeName": "firstName",
        "value": "Natasha",
        "otherValue": "MARIE"
    },
    {
        "attributeName": "lastName",
        "value": "Locke",
        "otherValue": "SOPHIE"
    }
]

Example 2

 vCompareResult1:=New collection

 vCompareResult2:=New collection

 vCompareResult3:=New collection

 $attributesToInspect:=New collection

 

 $e1:=ds.Employee.get(636)

 $e2:=ds.Employee.get(636)

 

 $e1.firstName:=$e1.firstName+" update"

 $e1.lastName:=$e1.lastName+" update"

 

 $c:=ds.Company.get(117)

 $e1.employer:=$c

 $e2.salary:=100

 

 $attributesToInspect.push("firstName")

 $attributesToInspect.push("lastName")

 

 vCompareResult1:=$e1.diff($e2)

 vCompareResult2:=$e1.diff($e2;$attributesToInspect)

 vCompareResult3:=$e1.diff($e2;$e1.touchedAttributes())

vCompareResult1 (all differences are returned):

[
    {
        "attributeName": "firstName",
        "value": "Karla update",
        "otherValue": "Karla"
    },
    {
        "attributeName": "lastName",
        "value": "Marrero update",
        "otherValue": "Marrero"
    },
    {
        "attributeName": "salary",
        "value": 33500,
        "otherValue": 100
    },
    {
        "attributeName": "employerID",
        "value": 117,
        "otherValue": 118
    },
  {
        "attributeName": "employer",
        "value": "[object Entity]",// Entity 117 from Company
        "otherValue": "[object Entity]"// Entity 118 from Company
    }
]

vCompareResult2 (only differences on $attributesToInspect are returned)

[
    {
        "attributeName": "firstName",
        "value": "Karla update",
        "otherValue": "Karla"
    },
    {
        "attributeName": "lastName",
        "value": "Marrero update",
        "otherValue": "Marrero"
    }
]

vCompareResult3 (only differences on $e1 touched attributes are returned)

[
    {
        "attributeName": "firstName",
        "value": "Karla update",
        "otherValue": "Karla"
    },
    {
        "attributeName": "lastName",
        "value": "Marrero update",
        "otherValue": "Marrero"
    },
    {
        "attributeName": "employerID",
        "value": 117,
        "otherValue": 118
    },
     {
        "attributeName": "employer",
        "value": "[object Entity]",// Entity 117 from Company
        "otherValue": "[object Entity]"// Entity 118 from Company

    }
]