重新编写了测试代码，增加了aggregate的实现

lib/store.d.ts

@@ -1,4 +1,4 @@
-import { DeduceCreateSingleOperation, DeduceRemoveOperation, DeduceUpdateOperation, OperationResult, OperateOption, OpRecord, EntityDict, SelectOption } from "oak-domain/lib/types/Entity";
+import { DeduceCreateSingleOperation, DeduceRemoveOperation, DeduceUpdateOperation, OperationResult, OperateOption, OpRecord, EntityDict, SelectOption, AggregationResult } from "oak-domain/lib/types/Entity";
 import { EntityDict as BaseEntityDict } from 'oak-domain/lib/base-app-domain';
 import { StorageSchema } from 'oak-domain/lib/types/Storage';
 import { NodeDict } from "./types/type";
@@ -53,8 +53,8 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
     protected updateAbjointRow<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends Context>(entity: T, operation: DeduceCreateSingleOperation<ED[T]['Schema']> | DeduceUpdateOperation<ED[T]['Schema']> | DeduceRemoveOperation<ED[T]['Schema']>, context: Cxt, option?: OP): number;
     protected selectAbjointRowAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends Context>(entity: T, selection: ED[T]['Selection'], context: Cxt, option?: OP): Promise<Partial<ED[T]["Schema"]>[]>;
     protected updateAbjointRowAsync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends Context>(entity: T, operation: DeduceCreateSingleOperation<ED[T]['Schema']> | DeduceUpdateOperation<ED[T]['Schema']> | DeduceRemoveOperation<ED[T]['Schema']>, context: Cxt, option?: OP): Promise<number>;
-    operateSync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends SyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP): OperationResult<ED>;
-    operateAsync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends AsyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP): Promise<OperationResult<ED>>;
+    protected operateSync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends SyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP): OperationResult<ED>;
+    protected operateAsync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends AsyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP): Promise<OperationResult<ED>>;
     /**
      * 计算最终结果集当中的函数，这个函数可能测试不够充分
      * @param entity
@@ -63,12 +63,23 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
      * @param nodeDict
      * @param context
      */
-    protected formExprInResult<T extends keyof ED, Cxt extends Context>(entity: T, projection: ED[T]['Selection']['data'], data: Partial<ED[T]['Schema']>, nodeDict: NodeDict, context: Cxt): void;
+    private formExprInResult;
     private formResult;
-    selectSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(entity: T, selection: ED[T]['Selection'], context: Cxt, option: OP): Partial<ED[T]['Schema']>[];
-    selectAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(entity: T, selection: ED[T]['Selection'], context: Cxt, option: OP): Promise<Partial<ED[T]["Schema"]>[]>;
-    countSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(entity: T, selection: Pick<ED[T]['Selection'], 'filter' | 'count'>, context: Cxt, option: OP): number;
-    countAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(entity: T, selection: Pick<ED[T]['Selection'], 'filter' | 'count'>, context: Cxt, option: OP): Promise<number>;
+    /**
+     * 本函数把结果中的相应属性映射成一个字符串，用于GroupBy
+     * @param entity
+     * @param row
+     * @param projection
+     */
+    private mappingProjectionOnRow;
+    private calcAggregation;
+    private formAggregation;
+    protected selectSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(entity: T, selection: ED[T]['Selection'], context: Cxt, option: OP): Partial<ED[T]['Schema']>[];
+    protected selectAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(entity: T, selection: ED[T]['Selection'], context: Cxt, option: OP): Promise<Partial<ED[T]["Schema"]>[]>;
+    protected aggregateSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(entity: T, aggregation: ED[T]['Aggregation'], context: Cxt, option: OP): AggregationResult<ED[T]['Schema']>;
+    protected aggregateAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(entity: T, aggregation: ED[T]['Aggregation'], context: Cxt, option: OP): Promise<AggregationResult<ED[T]['Schema']>>;
+    protected countSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(entity: T, selection: Pick<ED[T]['Selection'], 'filter' | 'count'>, context: Cxt, option: OP): number;
+    protected countAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(entity: T, selection: Pick<ED[T]['Selection'], 'filter' | 'count'>, context: Cxt, option: OP): Promise<number>;
     private addToTxnNode;
     getStat(): {
         create: number;

lib/store.js

@@ -5,6 +5,7 @@ var lodash_1 = require("oak-domain/lib/utils/lodash");
 var assert_1 = require("oak-domain/lib/utils/assert");
 var Entity_1 = require("oak-domain/lib/types/Entity");
 var Demand_1 = require("oak-domain/lib/types/Demand");
+var selection_1 = require("oak-domain/lib/store/selection");
 var Exception_1 = require("oak-domain/lib/types/Exception");
 var Demand_2 = require("oak-domain/lib/types/Demand");
 var relation_1 = require("oak-domain/lib/store/relation");
@@ -1118,6 +1119,176 @@ var TreeStore = /** @class */ (function (_super) {
             return rows2;
         }
     };
+    /**
+     * 本函数把结果中的相应属性映射成一个字符串，用于GroupBy
+     * @param entity
+     * @param row
+     * @param projection
+     */
+    TreeStore.prototype.mappingProjectionOnRow = function (entity, row, projection) {
+        var _this = this;
+        var key = '';
+        var result = {};
+        var values = [];
+        var mappingIter = function (entity2, row2, p2, result2) {
+            var e_12, _a;
+            var keys = Object.keys(p2).sort(function (ele1, ele2) { return ele1 < ele2 ? -1 : 1; });
+            try {
+                for (var keys_1 = tslib_1.__values(keys), keys_1_1 = keys_1.next(); !keys_1_1.done; keys_1_1 = keys_1.next()) {
+                    var k = keys_1_1.value;
+                    var rel = _this.judgeRelation(entity2, k);
+                    if (rel === 2) {
+                        result2[k] = {};
+                        if (row2[k]) {
+                            mappingIter(k, row2[k], p2[k], result2[k]);
+                        }
+                    }
+                    else if (typeof rel === 'string') {
+                        result2[k] = {};
+                        if (row2[k]) {
+                            mappingIter(rel, row2[k], p2[k], result2[k]);
+                        }
+                    }
+                    else {
+                        (0, assert_1.assert)([0, 1].includes(rel));
+                        result2[k] = row2[k];
+                        (0, assert_1.assert)(['string', 'number', 'boolean'].includes(typeof row2[k]));
+                        key += "".concat(row2[k]);
+                        values.push(row2[k]);
+                    }
+                }
+            }
+            catch (e_12_1) { e_12 = { error: e_12_1 }; }
+            finally {
+                try {
+                    if (keys_1_1 && !keys_1_1.done && (_a = keys_1.return)) _a.call(keys_1);
+                }
+                finally { if (e_12) throw e_12.error; }
+            }
+        };
+        mappingIter(entity, row, projection, result);
+        return {
+            result: result,
+            key: key,
+            values: values,
+        };
+    };
+    TreeStore.prototype.calcAggregation = function (entity, rows, aggregationData) {
+        var e_13, _a, e_14, _b, e_15, _c;
+        var ops = Object.keys(aggregationData).filter(function (ele) { return ele !== '$aggr'; });
+        var result = {};
+        try {
+            for (var rows_2 = tslib_1.__values(rows), rows_2_1 = rows_2.next(); !rows_2_1.done; rows_2_1 = rows_2.next()) {
+                var row = rows_2_1.value;
+                try {
+                    for (var ops_1 = (e_14 = void 0, tslib_1.__values(ops)), ops_1_1 = ops_1.next(); !ops_1_1.done; ops_1_1 = ops_1.next()) {
+                        var op = ops_1_1.value;
+                        var values = this.mappingProjectionOnRow(entity, row, aggregationData[op]).values;
+                        (0, assert_1.assert)(values.length === 1, "\u805A\u5408\u8FD0\u7B97\u4E2D\uFF0C".concat(op, "\u7684\u76EE\u6807\u5C5E\u6027\u591A\u4E8E1\u4E2A"));
+                        if (op.startsWith('$max')) {
+                            if (![undefined, null].includes(values[0]) && (!result.hasOwnProperty(op) || result[op] < values[0])) {
+                                result[op] = values[0];
+                            }
+                        }
+                        else if (op.startsWith('$min')) {
+                            if (![undefined, null].includes(values[0]) && (!result.hasOwnProperty(op) || result[op] > values[0])) {
+                                result[op] = values[0];
+                            }
+                        }
+                        else if (op.startsWith('$sum')) {
+                            if (![undefined, null].includes(values[0])) {
+                                (0, assert_1.assert)(typeof values[0] === 'number', '只有number类型的属性才可以计算sum');
+                                if (!result.hasOwnProperty(op)) {
+                                    result[op] = values[0];
+                                }
+                                else {
+                                    result[op] += values[0];
+                                }
+                            }
+                        }
+                        else if (op.startsWith('$count')) {
+                            if (![undefined, null].includes(values[0])) {
+                                if (!result.hasOwnProperty(op)) {
+                                    result[op] = 1;
+                                }
+                                else {
+                                    result[op] += 1;
+                                }
+                            }
+                        }
+                        else {
+                            (0, assert_1.assert)(op.startsWith('$avg'));
+                            if (![undefined, null].includes(values[0])) {
+                                (0, assert_1.assert)(typeof values[0] === 'number', '只有number类型的属性才可以计算avg');
+                                if (!result.hasOwnProperty(op)) {
+                                    result[op] = {
+                                        total: values[0],
+                                        count: 1,
+                                    };
+                                }
+                                else {
+                                    result[op].total += values[0];
+                                    result[op].count += 1;
+                                }
+                            }
+                        }
+                    }
+                }
+                catch (e_14_1) { e_14 = { error: e_14_1 }; }
+                finally {
+                    try {
+                        if (ops_1_1 && !ops_1_1.done && (_b = ops_1.return)) _b.call(ops_1);
+                    }
+                    finally { if (e_14) throw e_14.error; }
+                }
+            }
+        }
+        catch (e_13_1) { e_13 = { error: e_13_1 }; }
+        finally {
+            try {
+                if (rows_2_1 && !rows_2_1.done && (_a = rows_2.return)) _a.call(rows_2);
+            }
+            finally { if (e_13) throw e_13.error; }
+        }
+        try {
+            for (var ops_2 = tslib_1.__values(ops), ops_2_1 = ops_2.next(); !ops_2_1.done; ops_2_1 = ops_2.next()) {
+                var op = ops_2_1.value;
+                if (!result[op]) {
+                    result[op] = null;
+                }
+                else if (op.startsWith('$avg')) {
+                    result[op] = result[op].total / result[op].count;
+                }
+            }
+        }
+        catch (e_15_1) { e_15 = { error: e_15_1 }; }
+        finally {
+            try {
+                if (ops_2_1 && !ops_2_1.done && (_c = ops_2.return)) _c.call(ops_2);
+            }
+            finally { if (e_15) throw e_15.error; }
+        }
+        return result;
+    };
+    TreeStore.prototype.formAggregation = function (entity, rows, aggregationData) {
+        var _this = this;
+        var $aggr = aggregationData.$aggr;
+        if ($aggr) {
+            var groups_1 = (0, lodash_1.groupBy)(rows, function (row) {
+                var key = _this.mappingProjectionOnRow(entity, row, $aggr).key;
+                return key;
+            });
+            var result = Object.keys(groups_1).map(function (ele) {
+                var aggr = _this.calcAggregation(entity, groups_1[ele], aggregationData);
+                var r = _this.mappingProjectionOnRow(entity, groups_1[ele][0], $aggr).result;
+                aggr.data = r;
+                return aggr;
+            });
+            return result;
+        }
+        var aggr = this.calcAggregation(entity, rows, aggregationData);
+        return [aggr];
+    };
     TreeStore.prototype.selectSync = function (entity, selection, context, option) {
         var _this = this;
         (0, assert_1.assert)(context.getCurrentTxnId());
@@ -1144,6 +1315,64 @@ var TreeStore = /** @class */ (function (_super) {
             });
         });
     };
+    TreeStore.prototype.aggregateSync = function (entity, aggregation, context, option) {
+        var _this = this;
+        (0, assert_1.assert)(context.getCurrentTxnId());
+        var data = aggregation.data, filter = aggregation.filter, sorter = aggregation.sorter, indexFrom = aggregation.indexFrom, count = aggregation.count;
+        var p = {};
+        for (var k in data) {
+            Object.assign(p, (0, lodash_1.cloneDeep)(data[k]));
+        }
+        var selection = {
+            data: p,
+            filter: filter,
+            sorter: sorter,
+            indexFrom: indexFrom,
+            count: count,
+        };
+        (0, selection_1.reinforceSelection)(this.storageSchema, entity, selection);
+        var result = this.cascadeSelect(entity, selection, context, Object.assign({}, option, {
+            dontCollect: true,
+        }));
+        // 在这里再计算所有的表达式
+        result.forEach(function (ele) { return _this.formExprInResult(entity, selection.data, ele, {}, context); });
+        // 最后计算Aggregation
+        return this.formAggregation(entity, result, aggregation.data);
+    };
+    TreeStore.prototype.aggregateAsync = function (entity, aggregation, context, option) {
+        return tslib_1.__awaiter(this, void 0, void 0, function () {
+            var data, filter, sorter, indexFrom, count, p, k, selection, result;
+            var _this = this;
+            return tslib_1.__generator(this, function (_a) {
+                switch (_a.label) {
+                    case 0:
+                        (0, assert_1.assert)(context.getCurrentTxnId());
+                        data = aggregation.data, filter = aggregation.filter, sorter = aggregation.sorter, indexFrom = aggregation.indexFrom, count = aggregation.count;
+                        p = {};
+                        for (k in data) {
+                            Object.assign(p, (0, lodash_1.cloneDeep)(data[k]));
+                        }
+                        selection = {
+                            data: p,
+                            filter: filter,
+                            sorter: sorter,
+                            indexFrom: indexFrom,
+                            count: count,
+                        };
+                        (0, selection_1.reinforceSelection)(this.storageSchema, entity, selection);
+                        return [4 /*yield*/, this.cascadeSelectAsync(entity, selection, context, Object.assign({}, option, {
+                                dontCollect: true,
+                            }))];
+                    case 1:
+                        result = _a.sent();
+                        // 在这里再计算所有的表达式
+                        result.forEach(function (ele) { return _this.formExprInResult(entity, selection.data, ele, {}, context); });
+                        // 最后计算Aggregation
+                        return [2 /*return*/, this.formAggregation(entity, result, aggregation.data)];
+                }
+            });
+        });
+    };
     TreeStore.prototype.countSync = function (entity, selection, context, option) {
         var result = this.selectSync(entity, Object.assign({}, selection, {
             data: {
@@ -1206,7 +1435,7 @@ var TreeStore = /** @class */ (function (_super) {
         return uuid;
     };
     TreeStore.prototype.commitSync = function (uuid) {
-        var e_12, _a;
+        var e_16, _a;
         (0, assert_1.assert)(this.activeTxnDict.hasOwnProperty(uuid), uuid);
         var node = this.activeTxnDict[uuid].nodeHeader;
         while (node) {
@@ -1246,17 +1475,17 @@ var TreeStore = /** @class */ (function (_super) {
                 waiter.fn();
             }
         }
-        catch (e_12_1) { e_12 = { error: e_12_1 }; }
+        catch (e_16_1) { e_16 = { error: e_16_1 }; }
         finally {
             try {
                 if (_c && !_c.done && (_a = _b.return)) _a.call(_b);
             }
-            finally { if (e_12) throw e_12.error; }
+            finally { if (e_16) throw e_16.error; }
         }
         (0, lodash_1.unset)(this.activeTxnDict, uuid);
     };
     TreeStore.prototype.rollbackSync = function (uuid) {
-        var e_13, _a;
+        var e_17, _a;
         (0, assert_1.assert)(this.activeTxnDict.hasOwnProperty(uuid));
         var node = this.activeTxnDict[uuid].nodeHeader;
         while (node) {
@@ -1289,12 +1518,12 @@ var TreeStore = /** @class */ (function (_super) {
                 waiter.fn();
             }
         }
-        catch (e_13_1) { e_13 = { error: e_13_1 }; }
+        catch (e_17_1) { e_17 = { error: e_17_1 }; }
         finally {
             try {
                 if (_c && !_c.done && (_a = _b.return)) _a.call(_b);
             }
-            finally { if (e_13) throw e_13.error; }
+            finally { if (e_17) throw e_17.error; }
         }
         (0, lodash_1.unset)(this.activeTxnDict, uuid);
     };
@@ -1321,7 +1550,7 @@ var TreeStore = /** @class */ (function (_super) {
     };
     // 将输入的OpRecord同步到数据中
     TreeStore.prototype.sync = function (opRecords, context, option) {
-        var e_14, _a, e_15, _b;
+        var e_18, _a, e_19, _b;
         var option2 = Object.assign({}, option, {
             dontCollect: true,
             dontCreateOper: true,
@@ -1334,7 +1563,7 @@ var TreeStore = /** @class */ (function (_super) {
                         var e = record.e, d = record.d;
                         if (d instanceof Array) {
                             try {
-                                for (var d_1 = (e_15 = void 0, tslib_1.__values(d)), d_1_1 = d_1.next(); !d_1_1.done; d_1_1 = d_1.next()) {
+                                for (var d_1 = (e_19 = void 0, tslib_1.__values(d)), d_1_1 = d_1.next(); !d_1_1.done; d_1_1 = d_1.next()) {
                                     var dd = d_1_1.value;
                                     if (this.store[e] && this.store[e][dd.id]) {
                                         this.updateAbjointRow(e, {
@@ -1355,12 +1584,12 @@ var TreeStore = /** @class */ (function (_super) {
                                     }
                                 }
                             }
-                            catch (e_15_1) { e_15 = { error: e_15_1 }; }
+                            catch (e_19_1) { e_19 = { error: e_19_1 }; }
                             finally {
                                 try {
                                     if (d_1_1 && !d_1_1.done && (_b = d_1.return)) _b.call(d_1);
                                 }
-                                finally { if (e_15) throw e_15.error; }
+                                finally { if (e_19) throw e_19.error; }
                             }
                         }
                         else {
@@ -1435,12 +1664,12 @@ var TreeStore = /** @class */ (function (_super) {
                 }
             }
         }
-        catch (e_14_1) { e_14 = { error: e_14_1 }; }
+        catch (e_18_1) { e_18 = { error: e_18_1 }; }
         finally {
             try {
                 if (opRecords_1_1 && !opRecords_1_1.done && (_a = opRecords_1.return)) _a.call(opRecords_1);
             }
-            finally { if (e_14) throw e_14.error; }
+            finally { if (e_18) throw e_18.error; }
         }
     };
     return TreeStore;

src/store.ts

@@ -1,12 +1,13 @@
-import { cloneDeep, get, set, unset } from 'oak-domain/lib/utils/lodash';
+import { cloneDeep, get, groupBy, set, unset } from 'oak-domain/lib/utils/lodash';
 import { assert } from 'oak-domain/lib/utils/assert';
 import {
     DeduceCreateSingleOperation, DeduceFilter, DeduceSelection, EntityShape, DeduceRemoveOperation,
     DeduceUpdateOperation, DeduceSorter, DeduceSorterAttr, OperationResult, OperateOption, OpRecord,
     DeduceCreateOperationData, UpdateOpResult, RemoveOpResult, SelectOpResult,
-    EntityDict, SelectOption, DeleteAtAttribute
+    EntityDict, SelectOption, DeleteAtAttribute, AggregationResult, AggregationOp
 } from "oak-domain/lib/types/Entity";
 import { ExpressionKey, EXPRESSION_PREFIX, NodeId, RefAttr } from 'oak-domain/lib/types/Demand';
+import { reinforceSelection } from 'oak-domain/lib/store/selection';
 import { OakCongruentRowExists, OakException, OakRowUnexistedException } from 'oak-domain/lib/types/Exception';
 import { EntityDict as BaseEntityDict } from 'oak-domain/lib/base-app-domain';
 import { StorageSchema } from 'oak-domain/lib/types/Storage';
@@ -973,12 +974,12 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
     }
 
 
-    operateSync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends SyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP): OperationResult<ED> {
+    protected operateSync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends SyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP): OperationResult<ED> {
         assert(context.getCurrentTxnId());
         return this.cascadeUpdate(entity, operation, context, option);
     }
 
-    async operateAsync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends AsyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP) {
+    protected async operateAsync<T extends keyof ED, OP extends TreeStoreOperateOption, Cxt extends AsyncContext<ED>>(entity: T, operation: ED[T]['Operation'], context: Cxt, option: OP) {
         assert(context.getCurrentTxnId());
         return this.cascadeUpdateAsync(entity, operation, context, option);
     }
@@ -991,7 +992,7 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
      * @param nodeDict 
      * @param context 
      */
-    protected formExprInResult<T extends keyof ED, Cxt extends Context>(
+    private formExprInResult<T extends keyof ED, Cxt extends Context>(
         entity: T,
         projection: ED[T]['Selection']['data'],
         data: Partial<ED[T]['Schema']>,
@@ -1172,7 +1173,158 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
         }
     }
 
-    selectSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(
+    /**
+     * 本函数把结果中的相应属性映射成一个字符串，用于GroupBy
+     * @param entity 
+     * @param row 
+     * @param projection 
+     */
+    private mappingProjectionOnRow<T extends keyof ED>(
+        entity: T,
+        row: Partial<ED[T]['Schema']>,
+        projection: ED[T]['Selection']['data']
+    ) {
+        let key = '';
+        let result = {} as Partial<ED[T]['Schema']>;
+        const values = [] as any[];
+        const mappingIter = <T2 extends keyof ED>(
+            entity2: T2,
+            row2: Partial<ED[T2]['Schema']>,
+            p2: ED[T2]['Selection']['data'],
+            result2: Partial<ED[T2]['Schema']>) => {
+            const keys = Object.keys(p2).sort((ele1, ele2) => ele1 < ele2 ? -1 : 1);
+            for (const k of keys) {
+                const rel = this.judgeRelation(entity2, k);
+                if (rel === 2) {
+                    (result2 as any)[k] = {};
+                    if (row2[k]) {
+                        mappingIter(k, row2[k]!, p2[k], result2[k]!);
+                    }
+                }
+                else if (typeof rel === 'string') {
+                    (result2 as any)[k] = {};
+                    if(row2[k]) {
+                        mappingIter(rel, row2[k]!, p2[k], result2[k]!);
+                    }
+                }
+                else {
+                    assert([0, 1].includes(rel as number));
+                    (result2 as any)[k] = row2[k];
+                    assert(['string', 'number', 'boolean'].includes(typeof row2[k]));
+                    key += `${row2[k]}`;
+                    values.push(row2[k]);
+                }
+            }
+        };
+
+        mappingIter(entity, row, projection, result);
+        return {
+            result,
+            key,
+            values,
+        };
+    }
+
+    private calcAggregation<T extends keyof ED>(
+        entity: T,
+        rows: Partial<ED[T]['Schema']>[],
+        aggregationData: ED[T]['Aggregation']['data']
+    ) {
+        const ops = Object.keys(aggregationData).filter(
+            ele => ele !== '$aggr'
+        ) as AggregationOp [];
+        const result = {} as Record<string, any>;
+        for (const row of rows) {
+            for (const op of ops) {
+                const { values } = this.mappingProjectionOnRow(entity, row, (aggregationData as any)[op]);
+                assert(values.length === 1, `聚合运算中，${op}的目标属性多于1个`);
+                if (op.startsWith('$max')) {
+                    if (![undefined, null].includes(values[0]) && (!result.hasOwnProperty(op) || result[op] < values[0])) {
+                        result[op] = values[0];
+                    }
+                }
+                else if (op.startsWith('$min')) {
+                    if (![undefined, null].includes(values[0]) && (!result.hasOwnProperty(op) || result[op] > values[0])) {
+                        result[op] = values[0];
+                    }
+                }
+                else if (op.startsWith('$sum')) {
+                    if (![undefined, null].includes(values[0])) {
+                        assert(typeof values[0] === 'number', '只有number类型的属性才可以计算sum');
+                        if (!result.hasOwnProperty(op)) {
+                            result[op] = values[0];
+                        }
+                        else {
+                            result[op] += values[0];
+                        }
+                    }
+                }
+                else if (op.startsWith('$count')) {
+                    if (![undefined, null].includes(values[0])) {
+                        if (!result.hasOwnProperty(op)) {
+                            result[op] = 1;
+                        }
+                        else {
+                            result[op] += 1;
+                        }
+                    }
+                }
+                else {
+                    assert(op.startsWith('$avg'));
+                    if (![undefined, null].includes(values[0])) {
+                        assert(typeof values[0] === 'number', '只有number类型的属性才可以计算avg');
+                        if (!result.hasOwnProperty(op)) {
+                            result[op] = {
+                                total: values[0],
+                                count: 1,
+                            };
+                        }
+                        else {
+                            result[op].total += values[0];
+                            result[op].count += 1;
+                        }
+                    }
+
+                }
+            }
+        }
+        for (const op of ops) {
+            if (!result[op]) {
+                result[op] = null;
+            }
+            else if (op.startsWith('$avg')) {
+                result[op] = result[op].total/result[op].count;
+            }
+        }
+        return result as AggregationResult<ED[T]['Schema']>[number];
+    }
+
+    private formAggregation<T extends keyof ED, Cxt extends Context>(
+        entity: T,
+        rows: Array<Partial<ED[T]['Schema']>>,
+        aggregationData: ED[T]['Aggregation']['data']) {
+        const { $aggr } = aggregationData;
+        if ($aggr) {
+            const groups = groupBy(rows, (row) => {
+                const { key } = this.mappingProjectionOnRow(entity, row, $aggr);
+                return key;
+            });
+            const result = Object.keys(groups).map(
+                (ele) => {
+                    const aggr = this.calcAggregation(entity, groups[ele], aggregationData);
+                    const { result: r } = this.mappingProjectionOnRow(entity, groups[ele][0], $aggr);
+                    aggr.data = r;
+                    return aggr;
+                }
+            );
+
+            return result;
+        }
+        const aggr = this.calcAggregation(entity, rows, aggregationData);
+        return [ aggr ];
+    }
+
+    protected selectSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(
         entity: T,
         selection: ED[T]['Selection'],
         context: Cxt,
@@ -1186,7 +1338,7 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
         return result;
     }
 
-    async selectAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(
+    protected async selectAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(
         entity: T,
         selection: ED[T]['Selection'],
         context: Cxt,
@@ -1200,7 +1352,71 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
         return result;
     }
 
-    countSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(
+    protected aggregateSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(
+        entity: T,
+        aggregation: ED[T]['Aggregation'],
+        context: Cxt,
+        option: OP): AggregationResult<ED[T]['Schema']> {
+        assert(context.getCurrentTxnId());
+        const { data, filter, sorter, indexFrom, count } = aggregation;
+        const p: ED[T]['Selection']['data'] = {};
+        for (const k in data) {
+            Object.assign(p, cloneDeep((data as any)[k]));
+        }
+        const selection: ED[T]['Selection'] = {
+            data: p,
+            filter,
+            sorter,
+            indexFrom,
+            count,
+        };
+        reinforceSelection(this.storageSchema, entity, selection);
+
+        const result = this.cascadeSelect(entity, selection, context, Object.assign({}, option, {
+            dontCollect: true,
+        }));
+        // 在这里再计算所有的表达式
+        result.forEach(
+            (ele) => this.formExprInResult(entity, selection.data, ele, {}, context)
+        );
+
+        // 最后计算Aggregation
+        return this.formAggregation(entity, result, aggregation.data);
+    }
+
+    protected async aggregateAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(
+        entity: T,
+        aggregation: ED[T]['Aggregation'],
+        context: Cxt,
+        option: OP): Promise<AggregationResult<ED[T]['Schema']>> {
+        assert(context.getCurrentTxnId());
+        const { data, filter, sorter, indexFrom, count } = aggregation;
+        const p: ED[T]['Selection']['data'] = {};
+        for (const k in data) {
+            Object.assign(p, cloneDeep((data as any)[k]));
+        }
+        const selection: ED[T]['Selection'] = {
+            data: p,
+            filter,
+            sorter,
+            indexFrom,
+            count,
+        };
+        reinforceSelection(this.storageSchema, entity, selection);
+
+        const result = await this.cascadeSelectAsync(entity, selection, context, Object.assign({}, option, {
+            dontCollect: true,
+        }));
+        // 在这里再计算所有的表达式
+        result.forEach(
+            (ele) => this.formExprInResult(entity, selection.data, ele, {}, context)
+        );
+
+        // 最后计算Aggregation
+        return this.formAggregation(entity, result, aggregation.data);
+    }
+
+    protected countSync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends SyncContext<ED>>(
         entity: T,
         selection: Pick<ED[T]['Selection'], 'filter' | 'count'>,
         context: Cxt, option: OP): number {
@@ -1215,7 +1431,7 @@ export default class TreeStore<ED extends EntityDict & BaseEntityDict> extends C
         return typeof selection.count === 'number' ? Math.min(result.length, selection.count) : result.length;
     }
 
-    async countAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(
+    protected async countAsync<T extends keyof ED, OP extends TreeStoreSelectOption, Cxt extends AsyncContext<ED>>(
         entity: T,
         selection: Pick<ED[T]['Selection'], 'filter' | 'count'>,
         context: Cxt, option: OP) {

test/Context.ts

@@ -2,6 +2,7 @@ import TreeStore from '../src/store';
 import { EntityDict } from 'oak-domain/lib/base-app-domain';
 import { SyncContext, SyncRowStore } from "oak-domain/lib/store/SyncRowStore";
 import { OperateOption, OperationResult, SelectOption, AggregationResult, TxnOption, StorageSchema } from "oak-domain/lib/types";
+import { reinforceSelection } from 'oak-domain/lib/store/selection';
 
 /**
  * 实现一个同步的context和store用于测试
@@ -26,13 +27,14 @@ export class FrontendStore extends TreeStore<EntityDict> implements SyncRowStore
         return this.operateSync(entity, operation, context, option);
     }
     select<T extends keyof EntityDict, OP extends SelectOption>(entity: T, selection: EntityDict[T]["Selection"], context: FrontendRuntimeContext, option: OP): Partial<EntityDict[T]["Schema"]>[] {
+        reinforceSelection(this.storageSchema, entity, selection);
         return this.selectSync(entity, selection, context, option);
     }
     count<T extends keyof EntityDict, OP extends SelectOption>(entity: T, selection: Pick<EntityDict[T]["Selection"], "count" | "filter">, context: FrontendRuntimeContext, option: OP): number {
         return this.countSync(entity, selection, context, option);
     }
     aggregate<T extends keyof EntityDict, OP extends SelectOption>(entity: T, aggregation: EntityDict[T]["Aggregation"], context: FrontendRuntimeContext, option: OP): AggregationResult<EntityDict[T]["Schema"]> {
-        throw new Error("Method not implemented.");
+        return this.aggregateSync(entity, aggregation, context, option);
     }
     begin(option?: TxnOption | undefined): string {
         return this.beginSync();

test/test.ts

@@ -81,7 +81,6 @@ describe('基础测试', function () {
         context.commit();
     });
 
-
     it('[1.1]子查询', () => {
         const store = new FrontendStore(storageSchema);
         const context = new FrontendRuntimeContext(store);
@@ -154,7 +153,7 @@ describe('基础测试', function () {
         context.commit();
     });
 
-    it('[1.2]行内属性上的表达式', async () => {
+    it('[1.2]行内属性上的表达式', () => {
         const store = new FrontendStore(storageSchema);
         const context = new FrontendRuntimeContext(store);
         context.begin();
@@ -218,7 +217,7 @@ describe('基础测试', function () {
         context.commit();
     });
 
-    it('[1.3]跨filter结点的表达式', async () => {
+    it('[1.3]跨filter结点的表达式', () => {
         const store = new FrontendStore(storageSchema);
         const context = new FrontendRuntimeContext(store);
         context.begin();
@@ -433,7 +432,6 @@ describe('基础测试', function () {
                 entity: 1,
                 modi: {
                     id: 1,
-                    entity: 1,
                     $expr: {
                         $eq: [
                             {
@@ -526,7 +524,7 @@ describe('基础测试', function () {
                     data: {
                         id: 1,
                         entity: 1,
-                        modiId: 1,
+                        // modiId: 1,
                         $expr: {
                             $eq: [
                                 {
@@ -554,7 +552,7 @@ describe('基础测试', function () {
         context.commit();
     });
 
-    it('[1.7]事务性测试', async () => {
+    it('[1.7]事务性测试', () => {
         const store = new FrontendStore(storageSchema);
         const context = new FrontendRuntimeContext(store);
         context.begin();
@@ -643,5 +641,90 @@ describe('基础测试', function () {
 
         context.commit();
     });
+
+    it('[1.8]aggregate', () => {
+        const store = new FrontendStore(storageSchema);
+        const context = new FrontendRuntimeContext(store);
+        context.begin();
+        store.operate('modi', {
+            id: generateNewId(),
+            action: 'create',
+            data: [{
+                id: generateNewId(),
+                targetEntity: 'ddd',
+                entity: 'user',
+                entityId: 'user-id-1',
+                action: 'create',
+                data: {},
+                modiEntity$modi: {
+                    action: 'create',
+                    data: [{
+                        id: generateNewId(),
+                        entity: 'user',
+                        entityId: 'user-id-1',
+                    }, {
+                        id: generateNewId(),
+                        entity: 'user',
+                        entityId: 'user-id-1',
+                    }, {
+                        id: generateNewId(),
+                        entity: 'user',
+                        entityId: 'user-id-1',
+                    }, {
+                        id: generateNewId(),
+                        entity: 'user',
+                        entityId: 'user-id-1',
+                    }]
+                }
+            }, {
+                id: generateNewId(),
+                targetEntity: 'ddd2',
+                entity: 'user',
+                entityId: 'user-id-2',
+                action: 'create',
+                data: {},
+                modiEntity$modi: {
+                    action: 'create',
+                    data: [
+                        {
+                            id: generateNewId(),
+                            entity: 'user',
+                            entityId: 'user-id-2',
+                        },
+                        {
+                            id: generateNewId(),
+                            entity: 'user',
+                            entityId: 'user-id-2',
+                        },
+                        {
+                            id: generateNewId(),
+                            entity: 'user',
+                            entityId: 'user-id-2',
+                        }
+                    ],
+                },
+            }],
+        }, context, {});
+        context.commit();
+
+        context.begin();
+        const result = store.aggregate('modiEntity', {
+            data: {
+                '$count-1': {
+                    id: 1,
+                },
+                '$avg-1': {
+                    $$createAt$$: 1,
+                },
+                $aggr: {
+                    modi: {
+                        targetEntity: 1,
+                    }
+                }
+            },
+        }, context, {});
+        // console.log(result);
+        context.commit();
+    });
 });