MongoDB 国外文献查找过滤

Question

我 user collection 有角色 object 有 roleId。我还有 roles collection 有 id。现在，对于每个角色，我想获取用户列表。

例如：

[
    {
        "name": "Scott",
        "isActive": true,
        "role": {
            "roleId": "123432"
        }
    },
    {
        "name": "John",
        "isActive": true,
        "role": {
            "roleId": "123432"
        }
    },
    {
        "name": "Scott",
        "isActive": true,
        "role": {
            "roleId": "556432"
        }
    }
]

角色数据：

[
    {
        "id": "123432"
        "name": "admin",
        "type": "internal"
    },
    {
        "id": "556432"
        "name": "owner",
        "type": "external"
    },
    {
        "id": "556432"
        "name": "owner",
        "type": "internal"
    } 
]

现在我想获取internal类型的所有角色及其相关用户：

所以，输出应该是，

[
    {
       "role": "123432",
        "users": [
            {
                "name": "Scott",
                "role": {
                    "roleId": "123432"
                }
            },
            {
                "name": "John",
                "role": {
                    "roleId": "123432"
                }
            }
        ],
        { 
            "role": "556432",
            "users": []
         }
    }
]

这是我在 SpringBoort 中的聚合：

LookupOperation lookupOperation = LookupOperation.newLookup().from("roles").localField("roleId")
                .foreignField("_id").as("roles");

        AggregationOperation match = Aggregation.match(Criteria.where("type").is("internal"));

        Aggregation aggregation = Aggregation.newAggregation(lookupOperation, match);

        List<UserDTO> results = mongoTemplate.aggregate(aggregation, "users", UserDTO.class).getMappedResults();

但这不起作用。匹配过滤器 ois 使用主 table（用户）字段。但它不适用于外国 collection(roles)

有人可以帮我解决这个问题吗？

Answer 1

AggregationOperation isActiveMatch= Aggregation.match(Criteria.where("isActive").is(true)); 应该是第一场比赛。

LookupOperation lookupOperation = LookupOperation.newLookup().from("roles").localField("roleId")
                .foreignField("_id").as("roles");

AggregationOperation match = Aggregation.match(Criteria.where("type").is("internal"));

Aggregation aggregation = Aggregation.newAggregation(isActiveMatch,lookupOperation, match);

更新 1

你可能会这样期待，

db.user.aggregate([
  {
    "$lookup": {
      "from": "roles",
      "localField": "role.roleId",
      "foreignField": "id",
      "as": "roles"
    }
  },
  {
    $project: {
      roles: {
        "$filter": {
          "input": "$roles",
          "cond": {
            $eq: [
              "$$this.type",
              "internal"
            ]
          }
        }
      }
    }
  },
  {
    $match: {
      roles: {
        $ne: []
      }
    }
  }
])

工作Mongo playground

这里需要在lookup之后添加两个stage。第一个是过滤区间，第二个是消除空角色数组。

ProjectionOperation as =
        project()
            .and(
                ArrayOperators.Filter.filter("roles")
                    .as("role")
                    .by(ComparisonOperators.Eq.valueOf("role.type").equalTo("interval")))
            .as("roles");

我已经添加了项目阶段，希望您可以添加匹配阶段。以上代码未经测试，是根据工作脚本编写的。

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