需要在mgo中使用分页 [英] Need to use pagination in mgo
本文介绍了需要在mgo中使用分页的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我将Go用作后端，将MongoDB用作数据库，并使用beego框架来开发此应用程序.我想在前端进行分页.
我的结构如下:
type Employee struct {
Name string
EmpId string
Password string
PhoneNumber int32
EmailAddress string
Position string
AccessLevel string
Gender string
MaritalStatus string
Nationality string
Department string
ICNumber string
JoinDate time.Time
ConfirmationDate time.Time
EndDate time.Time
AnnualLeave []*AnnualLeaveInfo
MedicalLeave []*MedicalLeaveInfo
NopayLeave []*NopayLeaveInfo
ChildcareLeave []*ChildcareLeaveInfo
}
type AnnualLeaveInfo struct {
Id int
Days float64
Type string
From time.Time
To time.Time
AppliedDate time.Time
Status string
Certificate []*CertificateInfo
}
其他请假信息与年假信息相同.我想显示所有雇员文件的所有叶子，这些叶子按适用的日期和状态排序.现在，我要获取所有休假详细信息，然后追加到数组中，然后使用游标值(在上一个响应中传递到前端的数组的最后检索索引值)并从数组中查找值.我知道这不是一个很好的功能，因为对于每个请求，它都需要检索所有请假详细信息，以便仅检索前端请求的20个请假详细信息.
添加到数组中后，我的结果是这样的
"0": {
"LeaveEmpId": "rajeshk",
"Name": "rahul",
"LeaveId": 8,
"LeaveType": "annualleave",
"LeaveTotal": 2,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:29:33.713+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"1": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 7,
"LeaveType": "medicalleave",
"LeaveTotal": 3,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:27:06.12+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"2": {
"LeaveEmpId": "kumar",
"LeaveName": "madia",
"LeaveId": 6,
"LeaveType": "nopayleave",
"LeaveTotal": 4,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:11:58.283+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"3": {
"LeaveEmpId": "master",
"LeaveName": "kumar",
"LeaveId": 5,
"LeaveType": "nopayleave",
"LeaveTotal": 5,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:02:17.565+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"4": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 4,
"LeaveType": "medicalleave",
"LeaveTotal": 6,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:52:20.185+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"5": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 3,
"LeaveType": "annualleave",
"LeaveTotal": 7,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:49:18.702+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"6": {
"LeaveEmpId": "india",
"LeaveName": "rahul",
"LeaveId": 2,
"LeaveType": "nopayleave",
"LeaveTotal": 8,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:30:14.99+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"7": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 1,
"LeaveType": "medicalleave",
"LeaveTotal": 9,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:28:02.785+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
}
在数据库中，我的Empid仅是我使用的索引，该索引是唯一的，其他值不是唯一的.假ID仅在假数组中才是唯一的.有人可以帮助我如何有效地做到这一点.感谢任何帮助.谢谢.
添加的信息:
我的数据库结构如下所示...这只是一个员工的信息.像这样，我有很多员工文件.我需要获取所有这些员工文档的总请假详细信息，其中分页的限制为20个(按应用日期和状态排序).谢谢
{
"_id" : ObjectId("58320cec720fed31a3243683"),
"name" : "Rajesh",
"empid" : "rajeshk",
"password" : "c1e1a43a3d65ff4d669f2831b9908acb9e2f755c48280e99f0d7a3e92592fa29",
"phonenumber" : 0,
"emailaddress" : "example@example.com.sg",
"position" : "string",
"accesslevel" : "string",
"gender" : "string",
"maritalstatus" : "string",
"nationality" : "india",
"department" : "it",
"icnumber" : "string",
"childcitizenship" : "string",
"joindate" : ISODate("2015-11-21T00:00:00.000Z"),
"confirmationdate" : Date(-62135596800000),
"enddate" : Date(-62135596800000),
"totalchild" : 0,
"annualleave" : [
{
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"medicalleave" : [
{
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"nopayleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
},
{
"total" : 9.0,
"id" : 1,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:28:02.785Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 8.0,
"id" : 2,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:30:14.990Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 7.0,
"id" : 3,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:49:18.702Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 6.0,
"id" : 4,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:52:20.185Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 5.0,
"id" : 5,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:02:17.565Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 4.0,
"id" : 6,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:11:58.283Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 3.0,
"id" : 7,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:27:06.120Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 2.0,
"id" : 8,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:29:33.713Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
}
],
"childcareleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"hospitalleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"mdays" : 0.0,
"type" : "",
"daytype" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificatename" : "string",
"certificate" : []
}
],
"maternityleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"mdays" : 0.0,
"type" : "",
"daytype" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"paternityleave" : [
{
"total" : 0.0,
"id" : 0,
"days" : 0.0,
"mdays" : 0.0,
"type" : "",
"daytype" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"compassionateleave" : [
{
"total" : 0.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"marriageleave" : [
{
"total" : 0.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"otherleave" : []
}
解决方案
按原样，您无法真正实现更有效的分页，因为您要列出和分页的所有文档都在一个文档中，分成多个切片/阵列.
为了实现高效而简单的分页，我将重构您的模型.首先，我将所有类型的XXLeave文档存储为同一类型Leave，并向其添加一个属性，该属性可以告诉您该类型的休假(例如Annual，Medical等).接下来，我不会将此列表存储在Employee本身中，而是存储在单独的MongoDB集合中，并且它可能具有EmployeeID字段，告诉您Leave文档属于(所有者)属于哪个员工.
有了此模型，您可以使用以下查询轻松列出员工的Leave种特定类型的文档:
c := session.DB("").C("leaves")
err := c.Find(bson.M{"empid": eid, "type": LeaveAnnual}).All(&result)
要列出员工的所有Leave个文档，只需不使用"type"过滤器即可:
err := c.Find(bson.M{"empid": eid}).All(&result)
现在开始分页.如果您有这种模型，那么分页就成了小菜一碟:
q = c.Find(bson.M{"empid": eid}).Sort("applieddate", "status")
// Use Skip() and Limit() to denote the page you want to send, e.g.
q = Skip((page-1) * 20).Limit(20)
err := q.All(&result)
如果要发送所有Leave文档并对其进行分页，而与Employee(作者)无关，则还请省略EmpId过滤器:
err := c.Find(nil).Sort("applieddate", "status").
Skip((page-1) * 20).Limit(20).All(&result)
请注意，使用Skip()和Limit()可以很好地处理少量"的文档.但是对于大量文档，应基于指定起始索引条目使用分页.有关更多详细信息和现成的库，请参见此问题:
I am using Go as the back end and MongoDB as the database and use beego framework to develop this application. I would like to do some pagination in my front end.
My struct looks like this:
type Employee struct {
Name string
EmpId string
Password string
PhoneNumber int32
EmailAddress string
Position string
AccessLevel string
Gender string
MaritalStatus string
Nationality string
Department string
ICNumber string
JoinDate time.Time
ConfirmationDate time.Time
EndDate time.Time
AnnualLeave []*AnnualLeaveInfo
MedicalLeave []*MedicalLeaveInfo
NopayLeave []*NopayLeaveInfo
ChildcareLeave []*ChildcareLeaveInfo
}
type AnnualLeaveInfo struct {
Id int
Days float64
Type string
From time.Time
To time.Time
AppliedDate time.Time
Status string
Certificate []*CertificateInfo
}
The other leave info as same as the annual leave info. I would like to show all the leaves of all the employee documents sorted by applied date and status. Right now I'm retrieving all the leave details and then appending in array and then I am using the cursor value (last retrieved index value of the array which I pass to the front end in the previous response) and finding the values from the array. I know that this is not a good function because for every request it needs to retrieve all the leave details for retrieving only 20 leave details which is requested by the front end.
My Results after appending in the array is like this
"0": {
"LeaveEmpId": "rajeshk",
"Name": "rahul",
"LeaveId": 8,
"LeaveType": "annualleave",
"LeaveTotal": 2,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:29:33.713+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"1": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 7,
"LeaveType": "medicalleave",
"LeaveTotal": 3,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:27:06.12+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"2": {
"LeaveEmpId": "kumar",
"LeaveName": "madia",
"LeaveId": 6,
"LeaveType": "nopayleave",
"LeaveTotal": 4,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:11:58.283+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"3": {
"LeaveEmpId": "master",
"LeaveName": "kumar",
"LeaveId": 5,
"LeaveType": "nopayleave",
"LeaveTotal": 5,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T10:02:17.565+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"4": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 4,
"LeaveType": "medicalleave",
"LeaveTotal": 6,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:52:20.185+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"5": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 3,
"LeaveType": "annualleave",
"LeaveTotal": 7,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:49:18.702+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"6": {
"LeaveEmpId": "india",
"LeaveName": "rahul",
"LeaveId": 2,
"LeaveType": "nopayleave",
"LeaveTotal": 8,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:30:14.99+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
},
"7": {
"LeaveEmpId": "rajeshk",
"LeaveName": "Rajesh",
"LeaveId": 1,
"LeaveType": "medicalleave",
"LeaveTotal": 9,
"LeaveDays": 1,
"LeaveFrom": "2016-12-12T08:00:00+08:00",
"LeaveTo": "2016-12-12T08:00:00+08:00",
"LeaveAppliedDate": "2016-11-21T09:28:02.785+08:00",
"LeaveStatus": "Processing",
"CertificateName": [
"1.pdf",
"2.pdf"
]
}
In the database my empid is only index I use which is unique other values are not unique. Leave id is unique only with in the leave array. Can someone help me how to do this efficiently. Appreciate any help. Thanks.
Added Info:
My Database Structure looks like this ...This is just the info of one employee. Like this I have lots of employee documents. What I need is to get the total leave details of all these employee documents with the limit of 20 for pagination sorted by applieddate and status. Thanks
{
"_id" : ObjectId("58320cec720fed31a3243683"),
"name" : "Rajesh",
"empid" : "rajeshk",
"password" : "c1e1a43a3d65ff4d669f2831b9908acb9e2f755c48280e99f0d7a3e92592fa29",
"phonenumber" : 0,
"emailaddress" : "example@example.com.sg",
"position" : "string",
"accesslevel" : "string",
"gender" : "string",
"maritalstatus" : "string",
"nationality" : "india",
"department" : "it",
"icnumber" : "string",
"childcitizenship" : "string",
"joindate" : ISODate("2015-11-21T00:00:00.000Z"),
"confirmationdate" : Date(-62135596800000),
"enddate" : Date(-62135596800000),
"totalchild" : 0,
"annualleave" : [
{
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"medicalleave" : [
{
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"nopayleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
},
{
"total" : 9.0,
"id" : 1,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:28:02.785Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 8.0,
"id" : 2,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:30:14.990Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 7.0,
"id" : 3,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:49:18.702Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 6.0,
"id" : 4,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T01:52:20.185Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 5.0,
"id" : 5,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:02:17.565Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 4.0,
"id" : 6,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:11:58.283Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 3.0,
"id" : 7,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:27:06.120Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
},
{
"total" : 2.0,
"id" : 8,
"days" : 1.0,
"mdays" : 0.0,
"type" : "nopayleave",
"daytype" : "FullDay",
"from" : ISODate("2016-12-12T00:00:00.000Z"),
"to" : ISODate("2016-12-12T00:00:00.000Z"),
"applieddate" : ISODate("2016-11-21T02:29:33.713Z"),
"status" : "Processing",
"approveddate" : Date(-62135596800000),
"certificatename" : "",
"certificate" : [
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
},
{
"filename" : "Rajesh",
"filetype" : ".zip",
"filesize" : 1234
}
]
}
],
"childcareleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"hospitalleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"mdays" : 0.0,
"type" : "",
"daytype" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificatename" : "string",
"certificate" : []
}
],
"maternityleave" : [
{
"total" : 10.0,
"id" : 0,
"days" : 0.0,
"mdays" : 0.0,
"type" : "",
"daytype" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"paternityleave" : [
{
"total" : 0.0,
"id" : 0,
"days" : 0.0,
"mdays" : 0.0,
"type" : "",
"daytype" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"compassionateleave" : [
{
"total" : 0.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"marriageleave" : [
{
"total" : 0.0,
"id" : 0,
"days" : 0.0,
"type" : "",
"from" : Date(-62135596800000),
"to" : Date(-62135596800000),
"applieddate" : Date(-62135596800000),
"status" : "",
"approveddate" : Date(-62135596800000),
"certificate" : []
}
],
"otherleave" : []
}
解决方案
Being as it is, you can't really achieve a much more efficient pagination, since all the documents you want to list and paginate are in a single document, separated into multiple slices/arrays.
To achieve efficient and simple pagination, I would refactor your model. First I would store all kinds of XXLeave documents as the same type, Leave, and add a property to it which tells you what kind of leave it is (e.g. Annual, Medical etc.). Next, I would not store this list in the Employee itself, but rather in a separate MongoDB collection, and it could have an EmployeeID field, telling to which employee a Leave document belongs to (owner).
Having this model, you can easily list a specific type of Leave documents of an employee with a query like:
c := session.DB("").C("leaves")
err := c.Find(bson.M{"empid": eid, "type": LeaveAnnual}).All(&result)
To list all Leave documents of an employee, simply don't use the "type" filter:
err := c.Find(bson.M{"empid": eid}).All(&result)
Now on to pagination. If you have this model, pagination becomes a piece of cake:
q = c.Find(bson.M{"empid": eid}).Sort("applieddate", "status")
// Use Skip() and Limit() to denote the page you want to send, e.g.
q = Skip((page-1) * 20).Limit(20)
err := q.All(&result)
If you want to send and paginate over all Leave documents regardless of the Employee (the author), then also leave out the EmpId filter:
err := c.Find(nil).Sort("applieddate", "status").
Skip((page-1) * 20).Limit(20).All(&result)
Note that using Skip() and Limit() works great for "small" number of documents. But for large number of documents you should use pagination based on specifying starting index entry. See this question for more details and a ready-to-use library for it:
Efficient paging in MongoDB using mgo
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