Question

我已经用两个实体经理实现了存储库模式， mainManager用于只读和删除，updateManager用于编辑和添加新实体。我使用createEmptyCopy（）来创建updateManager。

在我更新实体之前，我从mainManager导出实体并导入到updateManager，在更改之后我调用了updateManager.saveChanges（）方法。

我注意到我在promise响应中找回了更新的实体。我想知道将这些实体导入mainManager的最佳做法是什么？

这是我的代码：

function ($q, $http, entityManagerFactory) {
    var self = this;

    self.mainManager = entityManagerFactory.newManager();
    self.updateManager = entityManagerFactory.newManager();

    self.saveChanges = function () {
        return self.updateManager.saveChanges();
    };

    self.rejectChanges = function() {
        self.updateManager.rejectChanges();
    };

    self.getDomains = function () {
        self.mainManager.clear();

        var query = new breeze.EntityQuery()
            .from('Domains')
            .orderBy('name');

        return self.mainManager.executeQuery(query);
    };

    self.createEmptyDomain = function () {
        var domain = self.updateManager.createEntity('Domain');

        return domain;
    };

    self.editDomain = function(domain) {
        var exported = self.mainManager.exportEntities([domain]);
        return self.updateManager.importEntities(exported).entities[0];
    }

    self.addDomain = function (domain) {
        self.updateManager.addEntity(domain);
        return self.updateManager.saveChanges();
    };

    self.deleteDomain = function (domain) {
        domain.entityAspect.setDeleted();
        var deferred = $q.defer();
        self.mainManager.saveChanges().then(
            function(data) {
                deferred.resolve(data);
            },
            function (reason) {
                console.log(reason);
                self.mainManager.rejectChanges();
                deferred.reject(reason);
            });

        return deferred.promise;
    };
}

现在我正在调用mainManager.clear（）并再次从服务器获取数据，如上面的getDomains函数所示。但我认为这太过于扩展，如果我已经拥有了saveChanges承诺中的更新实体，为什么要调用服务器呢？

我还尝试使用以下方法将这些实体导回mainManager：

mainManager.importEntities(data.entities, { mergeStrategy: breeze.MergeStrategy.OverwriteChanges });

但是我得到一个内部零微风异常：

TypeError: Cannot read property 'forEach' of undefined
    at EntityManager.proto.importEntities (breeze.debug.js:13081)
    at self.importEntities (domain-list.service.js:22)
    at domain-list.controller.js:70
    at processQueue (angular.js:13170)
    at angular.js:13186
    at Scope.promises.$get.Scope.$eval (angular.js:14383)
    at Scope.promises.$get.Scope.$digest (angular.js:14199)
    at Scope.promises.$get.Scope.$apply (angular.js:14488)
    at done (angular.js:9646)
    at completeRequest (angular.js:9836)

错误来自此行breeze.debug.js：13081

13080: var tempKeyMap = {}; 
13081:     json.tempKeys.forEach(function (k) { 
13082:       var oldKey = EntityKey.fromJSON(k, that.metadataStore); 
13083:       // try to use oldKey if not already used in this keyGenerator. 13084:       tempKeyMap[oldKey.toString()] = new EntityKey(oldKey.entityType, 
13085: that.keyGenerator.generateTempKeyValue(oldKey.entityType, oldKey.values[0])); 
13086:     });

Answer 1

var exportData = updateManager.exportEntities(data.entities, false);
                 mainManager.importEntities(exportData,
                    { mergeStrategy: breeze.MergeStrategy.OverwriteChanges });

如何在保存更改后通过两个实体管理器轻松导入实体

1 个答案: