1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
+++
date = "2015-07-16T14:27:51-04:00"
title = "Indexes"
[menu.main]
parent = "Builders"
weight = 60
pre = "<i class='fa'></i>"
+++
## Indexes
The [`Indexes`]({{< apiref "com/mongodb/client/model/Indexes" >}}) class provides static factory methods for all the MongoDB Index key types.
Each method returns an instance of the [`Bson`]({{< relref "bson/documents.md#bson" >}}) type, which can in turn be used with the `createIndex`
methods.
For brevity, you may choose to import the methods of the `Indexes` class statically:
```java
import static com.mongodb.client.model.Indexes.*;
```
All the examples below assume this static import.
### Ascending
To specify an ascending index key, use one of the [`ascending`]({{< apiref "com/mongodb/client/model/Indexes" >}}) methods.
This example specifies an ascending index key for the `quantity` field:
```java
ascending("quantity")
```
This example specifies a compound index key composed of the `quantity` field sorted in ascending order and the `totalAmount` field
sorted in ascending order:
```java
ascending("quantity", "totalAmount")
```
### Descending
To specify a descending index key, use one of the `descending` methods.
This example specifies a descending index key on the `quantity` field:
```java
descending("quantity")
```
This example specifies a compound index key composed of the `quantity` field sorted in descending order and the `totalAmount` field
sorted in descending order:
```java
descending("quantity", "totalAmount")
```
### Compound indexes
To specify a compound index, use the `compoundIndex` method.
This example specifies a compound index key composed of the `quantity` field sorted in ascending order, followed by the `totalAmount` field
sorted in ascending order, followed by the `orderDate` field sorted in descending order:
```java
compoundIndex(ascending("quantity", "totalAmount"), descending("orderDate"))
```
### Text Index
To specify a [text]({{< docsref "core/index-text" >}}) index key, use the `text` method.
This example specifies a text index key for the `description` field:
```java
text("description")
```
### Hashed Index
To specify a [hashed]({{< docsref "core/index-hashed" >}}) index key, use the `hashed` method.
This example specifies a hashed index key for the `timestamp` field:
```java
hashed("timestamp")
```
### Geospatial Indexes
There are also helpers for creating the index keys for the various [geospatial indexes]({{< docsref "applications/geospatial-indexes" >}})
supported by mongodb.
#### 2dsphere
To specify a [2dsphere]({{< docsref "core/2dsphere/" >}}) index key, use one of the `geo2dsphere` methods.
This example specifies a 2dsphere index on the `location` field:
```java
geo2dsphere("location")
```
#### 2d
To specify a [2d]({{< docsref "core/2d/" >}}) index key, use the `geo2d` method.
{{% note class="important"%}}
A 2d index is for data stored as points on a two-dimensional plane and is intended for legacy coordinate pairs used in MongoDB 2.2 and earlier.
{{% /note %}}
This example specifies a 2d index on the `points` field:
```java
geo2d("points")
```
#### geoHaystack
To specify a [geoHaystack]({{< docsref "core/geohaystack/" >}}) index key, use the `geoHaystack` method.
{{% note class="important"%}}
For queries that use spherical geometry, a 2dsphere index is a better option than a haystack index. 2dsphere indexes allow field reordering;
geoHaystack indexes require the first field to be the location field. Also, geoHaystack indexes are only usable via commands and so always
return all results at once.
{{% /note %}}
This example specifies a geoHaystack index on the `position` field and an ascending index on the `type` field:
```java
geoHaystack("position", ascending("type"))
```
|
