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Fundamentals

Atlas Search

在此页面上

  • Overview
  • 创建 Atlas Search 索引
  • Atlas Search 操作符
  • 自动完成(Autocomplete)
  • 多个子句
  • Equals
  • Exists
  • GeoShape
  • GeoWithin
  • 更多类似内容
  • Near
  • 短语
  • QueryString
  • 范围
  • 正则表达式(Regex)
  • span
  • Text
  • 通配符

Overview

在本指南中，您可以了解如何使用 Search 生成器，通过 MongoDB .NET/C# 驱动程序构建一个聚合管道阶段。

要了解有关 $search 管道阶段的更多信息，请参阅 $search。

注意

仅适用于 Atlas for MongoDB v4.2 及更高版本

$search聚合管道操作符仅适用于在运行MongoDB Atlas MongoDBv4.2 或更高版本的 集群上托管且由Atlas Search 索引 覆盖的集合。要详细了解此操作符所需的设置和功能，请参阅Atlas Search文档。

本指南中的示例使用名为 guitars 的集合中的以下文档：

{ "_id": 1, "make": "Fender", "description": "Classic guitars known for their versatility.", "establishedYear": 1946, "in-stock": true, "rating": 9 }
{ "_id": 2, "make": "Gibson", "description": "Classic guitars known for their rich, full tones.", "establishedYear": 1902, "in-stock": true, "rating": 8 }
{ "_id": 3, "make": "PRS", "description": "High-end guitars known for their quality.", "establishedYear": 1985, "in-stock": true, "rating": 9 }
{ "_id": 4, "make": "Kiesel", "description": "Quality guitars made only for custom orders.", "establishedYear": 2015, "in-stock": false }
{ "_id": 5, "make": "Ibanez", "description": "Well-crafted guitars used by many professional guitarists.", "establishedYear": 1957, "in-stock": true, "rating": 7 }
{ "_id": 6, "make": "Strandberg", "description": "Modern guitars known for their headless models.", "establishedYear": 1982, "in-stock": false }

以下 Guitar 类对此集合中的文档进行建模。

public class Guitar
{
    public int Id { get; set; }
    public string Make { get; set; }
    public List<string> Models { get; set; }
    public int EstablishedYear { get; set; }
    [BsonElement("in-stock")]
    public bool InStock { get; set; }
    public int? Rating { get; set; }
}

注意

guitars 集合中的文档使用驼峰命名约定。本指南中的示例使用 ConventionPack 将集合中的字段反序列化为 Pascal 语句，然后映射到 Guitar 类中的属性。

如需了解有关自定义序列化的更多信息，请参阅自定义序列化。

创建 Atlas Search 索引

在对 Atlas 集合进行搜索之前，您必须先在集合上创建一个 Atlas Search 索引。Atlas Search 索引是一种数据结构，它会以可搜索的格式对数据进行分类。

要了解如何创建 Atlas Search 索引，请参阅创建 Atlas Search 索引 Atlas 指南。

Atlas Search 操作符

Search类包含可用于执行$search操作的方法。 有关可用$search操作符的完整列表，请参阅 Atlas操作符和收集器指南。

注意

Search 类当前不支持 $embeddedDocument 操作符。

自动完成(Autocomplete)

使用 Autocomplete 方法，搜索包含不完整输入字符串中的字符序列的单词或短语。

以下示例使用 make 字段中的字符串“Gib”在 guitars 集合中执行自动补全搜索。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Autocomplete(g => g.Make, "Gib"))
    .ToList();

此搜索将返回如下文档：

{ "_id" : 2, "make" : "Gibson", "description" : "Classic guitars known for their rich, full tones.", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }

要了解有关 autocomplete 操作符的更多信息，请参阅 autocomplete Atlas 指南。

多个子句

使用 Compound 方法将两个或更多操作符组合到单次搜索中。

以下示例在 guitars 集合中搜索符合以下所有条件的任何文档：

  • 文档上存在 rating 字段

  • in-stock 字段不是 false

  • establishedYear 字段的值大于 1940

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Compound()
        .Must(Builders<Guitar>.Search.Exists(g => g.Rating))
        .MustNot(Builders<Guitar>.Search.Equals(g => g.InStock, false))
        .Must(Builders<Guitar>.Search.Range(g => g.EstablishedYear, SearchRangeBuilder.Gt(1940))))
    .ToList();

搜索会返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "...", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 3, "make" : "PRS", "description" : "...", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 5, "make" : "Ibanez", "description" : "...", "establishedYear" : 1957, "in-stock" : true, "rating" : 7 }

要了解有关 compound 操作符的更多信息，请参阅 compound Atlas 指南。

Equals

使用 Equals 方法检查字段是否与指定值匹配。

如下示例会在 guitars 集合中搜索 in-stock（有存货）字段值为 true 的任何文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Equals(g => g.InStock, true))
    .ToList();

搜索会返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "...", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 2, "make" : "Gibson", "description" : "...", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }
{ "_id" : 3, "make" : "PRS", "description" : "...", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 5, "make" : "Ibanez", "description" : "...", "establishedYear" : 1957, "in-stock" : true, "rating" : 7 }

要了解有关 equals 操作符的更多信息，请参阅 equals Atlas 指南。

Exists

使用 Exists 方法搜索其中存在指定索引字段名称的文档。如果指定的字段存在但没有为期创建索引，此文档不会包含在结果集内。

如下示例会在 guitars 集合中搜索存在 rating 字段的任何文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Exists(g => g.Rating))
    .ToList();

搜索会返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "...", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 2, "make" : "Gibson", "description" : "...", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }
{ "_id" : 3, "make" : "PRS", "description" : "...", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 5, "make" : "Ibanez", "description" : "...", "establishedYear" : 1957, "in-stock" : true, "rating" : 7 }

要了解有关 exists 操作符的更多信息，请参阅exists Atlas 指南。

GeoShape

使用 GeoShape 方法搜索与给定的几何图形相关的文档。当指定要搜索的坐标时，必须首先指定经度，然后指定纬度。经度值可以介于 -180 到 180（含）之间。纬度值可以介于 -90 到 90（含）之间。

注意

Atlas Search 不支持以下内容：

  • 非默认坐标参考系 (CRS)

  • 平面 XY 坐标系（二维）

  • 坐标对 点符号 (pointFieldName: [12, 34])

考虑到 guitars 集合中的某些文档已添加 in-stock-location 字段。现在，集合中的变更文档如下所示：

{ "_id": 1, "make": "Fender", "description": "...", "establishedYear": 1946, "in-stock": true, "in-stock-location":  { "type": "Point", "coordinates": [ -73.93615, 40.69791 ]}, "rating": 9 }
{ "_id": 2, "make": "Gibson", "description": "...", "establishedYear": 1902, "in-stock": true, "in-stock-location":  { "type": "Point", "coordinates": [ 47.6062, 122.321 ]}, "rating": 8 }

以下示例搜索 in-stock-location 字段中的坐标与指定多边形相交的所有文档：

GeoJsonPolygon<GeoJson2DGeographicCoordinates> searchArea = new(new(new(new GeoJson2DGeographicCoordinates[]
{
     new(-72.93615, 41.69791),
     new(-72.93615, 40.59791),
     new(-74.93615, 40.59791),
     new(-74.93615, 41.69791),
     new(-72.93615, 41.69791),
})));
var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.GeoShape(g => g.InStockLocation, GeoShapeRelation.Intersects, searchArea))
    .ToList();

此搜索将返回如下文档：

{ "_id" : 1, "make" : "Fender", "description" : "...", "establishedYear" : 1946, "in-stock" : true, "in-stock-location" : { "type" : "Point", "coordinates" : ["-73.93615", "40.69791"] }, "rating" : 9 }

要了解有关 geoShape 操作符的更多信息，请参阅 geoShape Atlas 指南。

GeoWithin

使用 GeoWithin 方法搜索指定 GeoJSON 字段坐标在给定几何范围内的文档。您可以搜索以下范围内的点：

  • 圆形

  • 边界框

  • 多边形

指定要搜索的坐标时，必须首先指定经度，然后指定纬度。经度值可以介于 -180 到 180 （含）之间。纬度值可以介于 -90 到 90（含）之间。

注意

Atlas Search 不支持以下内容：

  • 非默认坐标参考系 (CRS)

  • 平面 XY 坐标系（二维）

  • 坐标对 点符号 (pointFieldName: [12, 34])

考虑到 guitars 集合中的某些文档已添加 in-stock-location 字段。现在，集合中的变更文档如下所示：

{ "_id": 1, "make": "Fender", "description": "...", "establishedYear": 1946, "in-stock": true, "in-stock-location":  { "type": "Point", "coordinates": [ -73.93615, 40.69791 ]}, "rating": 9 }
{ "_id": 2, "make": "Gibson", "description": "...", "establishedYear": 1902, "in-stock": true, "in-stock-location":  { "type": "Point", "coordinates": [ 47.6062, 122.321 ]}, "rating": 8 }

以下示例会搜索 in-stock-location 字段中的坐标位于指定多边形内的所有文档：

GeoJsonPolygon<GeoJson2DGeographicCoordinates> searchArea = new(new(new(new GeoJson2DGeographicCoordinates[]
{
     new(-74.3994140625, 40.5305017757),
     new(-74.7290039063, 40.5805846641),
     new(-74.7729492188, 40.9467136651),
     new(-74.0698242188, 41.1290213475),
     new(-73.65234375, 40.9964840144),
     new(-72.6416015625, 40.9467136651),
     new(-72.3559570313, 40.7971774152),
     new(-74.3994140625, 40.5305017757),
})));
var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.GeoWithin(g => g.InStockLocation, searchArea))
    .ToList();

此搜索将返回如下文档：

{ "_id" : 1, "make" : "Fender", "description" : "Classic guitars known for their versatility.", "establishedYear" : 1946, "in-stock" : true, "in-stock-location" : { "type" : "Point", "coordinates" : ["-73.93615", "40.69791"] }, "rating" : 9 }

要了解有关 geoWithin 操作符的更多信息，请参阅 geoWithin Atlas 指南。

更多类似内容

使用 MoreLikeThis 方法搜索与输入文档类似的文档。

以下示例会在 guitars 集合中搜索与 Description 字段值为“high quality”的对象相似的文档。

var searchDocument = new GuitarSearch()
{
    Description = "high quality",
};
var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.MoreLikeThis(searchDocument))
    .ToList();

搜索会返回以下文档：

{ "_id" : 3, "make" : "PRS", "description" : "High-end guitars known for their quality.", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 4, "make" : "Kiesel", "description" : "Quality guitars made only for custom orders.", "establishedYear" : 2015, "in-stock" : false, "rating" : null }

要了解有关 moreLikeThis 操作符的更多信息，请参阅 moreLikeThis Atlas 指南。

Near

使用 Near 方法搜索指定的字段接近给定值的文档。您可以对以下对象执行搜索：

  • 数字字段

  • 日期字段

  • 地理点

以下示例会在 guitars 集合中搜索 rating 字段的值接近 9 的文档。根据该值与数字 9 的接近程度按顺序返回文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Near(g => g.Rating, 9, 1))
    .ToList();

搜索会返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "...", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 3, "make" : "PRS", "description" : "...", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 2, "make" : "Gibson", "description" : "...", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }
{ "_id" : 5, "make" : "Ibanez", "description" : "...", "establishedYear" : 1957, "in-stock" : true, "rating" : 7 }

要了解有关 near 操作符的更多信息，请参阅 near Atlas 指南。

短语

使用 Phrase 方法搜索指定字段包含输入字符串的文档。

如下示例将在 guitars 集合中搜索 description（说明）字段包含短语“classic guitars”的文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Phrase(g => g.Description, "classic guitars"))
    .ToList();

搜索会返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "Classic guitars known for their versatility.", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 2, "make" : "Gibson", "description" : "Classic guitars known for their rich, full tones.", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }

您还可以按以下方式搜索与多个单独短语匹配的文档：

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Phrase(g => g.Description, new List<string>() { "classic guitars", "quality guitars" }))
    .ToList();

此搜索将返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "Classic guitars known for their versatility.", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 4, "make" : "Kiesel", "description" : "Quality guitars made only for custom orders.", "establishedYear" : 2015, "in-stock" : false, "rating" : null }
{ "_id" : 2, "make" : "Gibson", "description" : "Classic guitars known for their rich, full tones.", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }

要了解有关 phrase 操作符的更多信息，请参阅短语 Atlas 指南。

QueryString

使用 QueryString 方法，将一个字符串与以下操作符和分隔符结合使用以搜索文档：

  • AND

  • OR

  • NOT

  • ()

以下示例会在 guitars 集合中搜索 description 字段的值与以下每个条件匹配的文档：

  • 包含字符串“classic”或字符串“quality”

  • 不包含字符串“自定义”

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.QueryString(g => g.Description, "(classic OR quality) AND NOT custom"))
    .ToList();

搜索会返回以下文档：

{ "_id" : 1, "make" : "Fender", "description" : "Classic guitars known for their versatility.", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 3, "make" : "PRS", "description" : "High-end guitars known for their quality.", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 2, "make" : "Gibson", "description" : "Classic guitars known for their rich, full tones.", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }

要了解有关 queryString 操作符的更多信息，请参阅 queryString Atlas 指南。

范围

使用 Range 方法搜索指定字段的值处于给定数字或日期范围内的文档。

以下示例会在 guitars 集合中搜索 establishedYear 值大于 1980 且小于 2020 的所有文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Range(g => g.EstablishedYear, SearchRangeBuilder.Gt(1980).Lt(2020)))
    .ToList();

此搜索将返回以下结果：

{ "_id" : 3, "make" : "PRS", "description" : "High-end guitars known for their quality.", "establishedYear" : 1985, "in-stock" : true, "rating" : 9 }
{ "_id" : 4, "make" : "Kiesel", "description" : "Quality guitars made only for custom orders.", "establishedYear" : 2015, "in-stock" : false, "rating" : null }
{ "_id" : 6, "make" : "Strandberg", "description" : "Modern guitars known for their headless models.", "establishedYear" : 1982, "in-stock" : false, "rating" : null }

要了解有关 range 操作符的更多信息，请参阅 range Atlas 指南。

正则表达式(Regex)

使用 Regex 方法使用正则表达式搜索文档。

以下示例会在 guitars 集合中搜索 make 字段的值恰好包含六个字母的文档。

var regex = "[A-Za-z]{6}";
var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Regex(g => g.Make, regex))
    .ToList();

此搜索将返回以下结果：

{ "_id" : 1, "make" : "Fender", "description" : "Classic guitars known for their versatility.", "establishedYear" : 1946, "in-stock" : true, "rating" : 9 }
{ "_id" : 2, "make" : "Gibson", "description" : "Classic guitars known for their rich, full tones.", "establishedYear" : 1902, "in-stock" : true, "rating" : 8 }
{ "_id" : 4, "make" : "Kiesel", "description" : "Quality guitars made only for custom orders.", "establishedYear" : 2015, "in-stock" : false, "rating" : null }
{ "_id" : 5, "make" : "Ibanez", "description" : "Well-crafted guitars used by many professional guitarists.", "establishedYear" : 1957, "in-stock" : true, "rating" : 7 }

注意

默认情况下，regex 操作符不能在分析字段上运行。您可以通过将 allowAnalyzedField 选项设置为 true，支持在分析字段上执行该操作符，如下所示：

var result = guitarsCollection.Aggregate()
 .Search(Builders<Guitar>.Search.Regex(g => g.Make, regex, true))
 .ToList();

将 allowAnalyzedField 选项设置为 true 可能会导致意外的搜索结果。要了解详情，请参阅 regex 行为。

要了解有关 regex 操作符的更多信息，请参阅 regex Atlas 指南。

span

使用 Span 方法，搜索字段区域内的文本搜索匹配项。您可以使用该方法，按照指定的精度查找相似的字符串。

注意

span 操作符比其他操作符的计算量更大，因为查询必须跟踪位置信息。

如下示例将在 guitars 集合中搜索 description（说明）字段的值包含彼此相邻的字符串“guitars”和“quality”的文档。

var searchTerms = new[]
{
     Builders<Guitar>.SearchSpan.Term(g => g.Description, "guitars"),
     Builders<Guitar>.SearchSpan.Term(g => g.Description, "quality")
 };
var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Span(Builders<Guitar>.SearchSpan.Near(searchTerms, 1)))
    .ToList();

此搜索将返回如下文档：

{ "_id" : 4, "make" : "Kiesel", "description" : "Quality guitars made only for custom orders.", "establishedYear" : 2015, "in-stock" : false, "rating" : null }

虽然带有 _id: 3 的文档包含字符串“guitars”和“quality”，但它们由多个单词分隔，搜索结果忽略了该文档。

要了解有关 span 操作员的更多信息，请参阅 span Atlas 指南。

Text

使用 Text 方法在文档中搜索给定的字符串或字符串数组。如果给定的字符串中有多个词，Atlas Search 还会分别为字符串中的每个词查找匹配项。

以下示例会在 guitars 集合中搜索 description 字段的值包含字符串“used by professionals”（专业人员使用）的文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Text(g => g.Description, "used by professional"))
    .ToList();

此搜索将返回如下文档：

{ "_id" : 5, "make" : "Ibanez", "description" : "Well-crafted guitars used by many professional guitarists.", "establishedYear" : 1957, "in-stock" : true, "rating" : 7 }

提示

如果您的搜索字符串包含多个术语，此方法还会分别查找字符串中的每个术语的匹配项。

要了解有关 text 操作符的更多信息，请参阅 text Atlas 指南。

通配符

使用 Wildcard 方法在搜索字符串中使用可以匹配任何字符的特殊字符来搜索文档。您可以在搜索中使用以下字符：

字符
说明
?
匹配任意单个字符。
*
匹配 0 个或更多字符。
\
转义字符

以下示例会搜索 make 字段的值包含字符串“Strand”，后跟任何其他字符的文档。

var result = guitarsCollection.Aggregate()
    .Search(Builders<Guitar>.Search.Wildcard(g => g.Make, "Strand*"))
    .ToList();

此搜索将返回如下文档：

{ "_id" : 6, "make" : "Strandberg", "description" : "Modern guitars known for their headless models.", "establishedYear" : 1982, "in-stock" : false, "rating" : null }

注意

默认情况下，wildcard 操作符不能在分析字段上运行。您可以通过将 allowAnalyzedField 选项设置为 true，支持在分析字段上执行该操作符，如下所示：

var result =  guitarsCollection.Aggregate()
 .Search(Builders<Guitar>.Search.Wildcard(g => g.Make, "Strand*", true))
 .ToList();

将 allowAnalyzedField 选项设置为 true，可能会导致意外的搜索结果。要了了解详情，请参阅 wildcard 行为。

要了解有关 wildcard 操作符的更多信息，请参阅 wildcard Atlas 指南。

后退

与构建者合作