如何在绑定到客户端控件之前对SAPUI5 OData进行分组？ [英] How to group SAPUI5 OData before bind to control at client side?

问题描述

我有一个例如JSON表示法的odata列表：

I have an odata list for example in JSON notation:

var data = [
 {"category" : "A", "value" : 1, "group" : "x"},
 {"category" : "B", "value" : 2, "group" : "y"},
 {"category" : "C", "value" : 3, "group" : "x"},
 {"category" : "A", "value" : 4, "group" : "y"},
 {"category" : "A", "value" : 5, "group" : "x"}
];

首先我过滤 group == x; 左边的值是：

First of all I filter against group == x; Values left are:

var data = [
 {"category" : "A", "value" : 1, "group" : "x"},
 {"category" : "C", "value" : 3, "group" : "x"},
 {"category" : "A", "value" : 5, "group" : "x"}
];

现在我将按类别分组（在客户端）并总结值，因此结果应该是be：

Now I would group (at client side) by category and sum up the values, so the result should be:

var data = [
 {"category" : "A", "value" : 6, },
 {"category" : "C", "value" : 3, },
];

之后我会将模型绑定到某个SAPUI5控件。

After that I would bind the model to some SAPUI5 control.

但分组部分似乎不可能。

But the grouping part seems not possible.

有人知道这个问题的通用解决方案吗？

Does someone know a generic solution for that problem?

潜在用例：

var oDataset = new sap.viz.ui5.data.FlattenedDataset({
    dimensions : [ {axis : 1, value : "{category}", name : "Category" } ],
    measures : [ {value : "{value}", name : "Value" } ],
    data : {
        path : "/Data"
    }
});

var oGraph = new sap.viz.ui5.Donut({
    dataset : oDataset, // sap.viz.ui5.data.Dataset
});

推荐答案

以下代码适用于我。通过通用绑定查询一些产品的Northwind Order_Details服务，map减少返回的绑定并将每个订单的数量汇总到销售的总量，在柱形图中显示结果。

The following code works for me. Query Northwind Order_Details service for a couple of Products via a generic binding, map reduce the the returned bindings and aggregate the Quantity of each order to the total Quanity sold, show the results in a column chart.

查看jsBin示例

注意sap.viz引入了Array.prototype.map和Array.prototype.reduce函数

note sap.viz introduces Array.prototype.map and Array.prototype.reduce functions

var sURI = 'http://services.odata.org/Northwind/Northwind.svc/';
var oDataModel = new sap.ui.model.odata.ODataModel(sURI, true);
oDataModel.setSizeLimit(10000);
var oJSONModel = new sap.ui.model.json.JSONModel({}, 'jmodel');

// handle list of contexts
var handler = function(oEvent) {
    var mapCallback = function(oContext) {
        var obj = {};
        obj.ProductID = oContext.getObject().ProductID,
        obj.Quantity = oContext.getObject().Quantity
        return obj;
    };

    var reduceCallback = function(aPrev, oCurr) {
        var aNext = aPrev;
        var bFound = false;

        aNext.forEach(function(item) {
            if (item.ProductID === oCurr.ProductID) {
                bFound = true;
                item.Quantity += oCurr.Quantity;
            }
        })

        if (bFound === false) {
            aNext.push(oCurr);
        }

        return aNext;
    };
    //release handler
    oBindings.detachChange(handler);

    var aTotals = oEvent.oSource.getContexts().map(mapCallback).reduce(reduceCallback, []);
    oJSONModel.setData({
        'Order_Totals': aTotals
    });
};

// Filter all orders by 3 products
var oFilter1 = new sap.ui.model.Filter("ProductID", sap.ui.model.FilterOperator.EQ, '1');
var oFilter2 = new sap.ui.model.Filter("ProductID", sap.ui.model.FilterOperator.EQ, '68');
var oFilter3 = new sap.ui.model.Filter("ProductID", sap.ui.model.FilterOperator.EQ, '11');
var aFilter = [oFilter1, oFilter2, oFilter3];

// Sort by ProductID
var oSorter = new sap.ui.model.Sorter("ProductID", false, true);

// Reduce the returned payload by nominating need fields
var oSelect = {
    select: 'ProductID,Quantity'
}

var oBindings = oDataModel.bindList("/Order_Details", null, oSorter, aFilter, oSelect);

// call OData service and handle results
oBindings.attachChange(handler);
oBindings.getContexts();

var oDataset = new sap.viz.ui5.data.FlattenedDataset({
    dimensions: [{
        axis: 1,
        name: 'ProductID',
        value: "{ProductID}"
    }],
    measures: [{
        name: 'Quantity Sold',
        value: '{Quantity}'
    }],
    data: {
        path: "/Order_Totals"
    }
});

var oColumnChart = new sap.viz.ui5.Column({
    width: "80%",
    height: "400px",
    plotArea: {
        'colorPalette': d3.scale.category20().range()
    },
    title: {
        visible: true,
        text: 'Qutantity Sold by Product'
    },
    dataset: oDataset
});

oColumnChart.setModel(oJSONModel);

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