Deep Download Feature¶

This feature is experimental and only available with an OData V4 backend. It allows downloading data from OData V4 backends with support for nested entities and relationships, handling complex data structures efficiently.

Triggering the Download¶

The spreadsheet download is triggered by a button in the spreadsheet upload dialog. This process is managed by the SpreadsheetUploadDialog.ts file.

onInitDownloadSpreadsheetProcess: This method initializes the download process. If config.showOptions is true, it opens the SpreadsheetDownloadDialog to allow users to set options. Otherwise, it triggers the download directly with default settings.
onSave: This method in SpreadsheetDownloadDialog.ts sets the deepDownloadConfig and calls onDownloadDataSpreadsheet.

Method onDownloadDataSpreadsheet¶

This method checks for errors before proceeding with the download. Errors can occur in the setContext method of SpreadsheetUpload.ts.

MetadataHandlerV4¶

The MetadataHandlerV4 class builds the metadata model, which is a tree of all entities and their properties. The entityName should be the root entity of the download, and deepLevel should be the maximum depth of the download.

_findEntitiesByNavigationProperty: This method traverses the metadata model and collects all entities related to the root entity by navigation properties. If the $kind and $Partner properties are present and the $ReferentialConstraint is not, the full entity is added to the parent entity as $XYZEntity, making it explicitly fetchable with $XYZFetchableEntity.

JSON Sample¶

This is the root entity without some properties for brevity before the navigation property was added:

{
    "$kind": "EntityType",
    "$Key": [
        "ID",
        "IsActiveEntity"
    ],
    "OrderNo": {
        "$kind": "Property",
        "$Type": "Edm.String",
        "$MaxLength": 22
    },
    "Items": {
        "$kind": "NavigationProperty",
        "$isCollection": true,
        "$Type": "OrdersService.OrderItems",
        "$Partner": "order",
        "$OnDelete": "Cascade"
    },
    "Shipping": {
        "$kind": "NavigationProperty",
        "$isCollection": true,
        "$Type": "OrdersService.ShippingDetails",
        "$Partner": "order",
        "$OnDelete": "Cascade"
    },
    "buyer": {
        "$kind": "Property",
        "$Type": "Edm.String",
        "$MaxLength": 255
    }
}

This is the root entity after navigation properties for Items (here Infos under Items) and Shipping were added:

{
    "$kind": "EntityType",
    "$Key": [
        "ID",
        "IsActiveEntity"
    ],
    "ID": {
        "$kind": "Property",
        "$Type": "Edm.Guid",
        "$Nullable": false
    },
    "OrderNo": {
        "$kind": "Property",
        "$Type": "Edm.String",
        "$MaxLength": 22
    },
    "Items": {
        "$kind": "NavigationProperty",
        "$isCollection": true,
        "$Type": "OrdersService.OrderItems",
        "$Partner": "order",
        "$OnDelete": "Cascade",
        "$XYZEntity": {
            "$kind": "EntityType",
            "$Key": [
                "ID",
                "IsActiveEntity"
            ],
            "ID": {
                "$kind": "Property",
                "$Type": "Edm.Guid",
                "$Nullable": false
            },
            "order": {
                "$kind": "NavigationProperty",
                "$Type": "OrdersService.Orders",
                "$Partner": "Items",
                "$ReferentialConstraint": {
                    "order_ID": "ID"
                }
            },
            "order_ID": {
                "$kind": "Property",
                "$Type": "Edm.Guid"
            },
            "product_ID": {
                "$kind": "Property",
                "$Type": "Edm.String"
            },
            "Infos": {
                "$kind": "NavigationProperty",
                "$isCollection": true,
                "$Type": "OrdersService.OrderItemsInfo",
                "$Partner": "orderItem",
                "$OnDelete": "Cascade",
                "$XYZEntity": {
                    "$kind": "EntityType",
                    "$Key": [
                        "ID",
                        "IsActiveEntity"
                    ],
                    "ID": {
                        "$kind": "Property",
                        "$Type": "Edm.Guid",
                        "$Nullable": false
                    },
                    "orderItem": {
                        "$kind": "NavigationProperty",
                        "$Type": "OrdersService.OrderItems",
                        "$Partner": "Infos",
                        "$ReferentialConstraint": {
                            "orderItem_ID": "ID"
                        }
                    },
                    "orderItem_ID": {
                        "$kind": "Property",
                        "$Type": "Edm.Guid"
                    },
                    "comment": {
                        "$kind": "Property",
                        "$Type": "Edm.String"
                    }
                },
                "$XYZFetchableEntity": true
            },
            "quantity": {
                "$kind": "Property",
                "$Type": "Edm.Int32"
            }
        },
        "$XYZFetchableEntity": true
    },
    "Shipping": {
        "$kind": "NavigationProperty",
        "$isCollection": true,
        "$Type": "OrdersService.ShippingDetails",
        "$Partner": "order",
        "$OnDelete": "Cascade",
        "$XYZEntity": {
            "$kind": "EntityType",
            "$Key": [
                "ID",
                "IsActiveEntity"
            ],
            "ID": {
                "$kind": "Property",
                "$Type": "Edm.Guid",
                "$Nullable": false
            },
            "order": {
                "$kind": "NavigationProperty",
                "$Type": "OrdersService.Orders",
                "$Partner": "Shipping",
                "$ReferentialConstraint": {
                    "order_ID": "ID"
                }
            },
            "order_ID": {
                "$kind": "Property",
                "$Type": "Edm.Guid"
            }
        },
        "$XYZFetchableEntity": true
    },
    "buyer": {
        "$kind": "Property",
        "$Type": "Edm.String",
        "$MaxLength": 255
    }
}

With this metadata model, it is much easier to fetch data and have an overview of all the entities related to the root entity.

Expands¶

The method _getExpandsRecursive is called to traverse the metadata model and create a list of expands for the OData binding, which is created in getBindingFromBinding in ODataV4.ts. The expands are used to fetch related entities in one request.

Binding¶

With the binding from the root entity, a custom binding is created with the expands in getBindingFromBinding in ODataV4.ts to fetch the data.

fetchBatch¶

The method fetchBatch in ODataV4.ts is used to fetch the data in batches of 1000. This is done to prevent the OData V4 backend from timing out. The data is requested with requestContexts from the binding, and the results are of type sap.ui.model.odata.v4.Context[] and returned in the variable totalResults.

extractObjects Method¶

The extractObjects method is used to process the fetched data and prepare it for spreadsheet generation.

Spreadsheet Generation¶

The SpreadsheetGenerator class handles the creation of the spreadsheet file. It uses the fetched data to generate sheets for each entity and its related entities, ensuring that all necessary data is included in the final output.