定义
语法
hasAncestor操作符的语法如下：
{ $search: { "index": "<index name>", // optional, defaults to "default" "hasAncestor": { "ancestorPath": "<embeddedDocuments-type-higher-level-field>", "operator": { <operator-specification> } }, "returnScope": { "path": "<embeddedDocuments-type-field-to-retrieve>" } }}字段
字段 | 类型 | 说明 | 必要性 |
|---|---|---|---|
| 字符串 |
| 必需 |
| 对象 | 用于查询 不能在操作符规范内使用 | 必需 |
要求
要使用该操作符，您必须：
将祖先字段索引为 embeddedDocuments 类型。在查询中，将
ancestorPath指定为此字段。如果该字段位于根级别，请使用 hasRoot。指定 returnScope 以设置要查询和检索的文档范围。
示例
本节中的示例使用sample_training.companies 数据集。如果您加载了示例数据集并在集合上创建索引，则可以尝试本部分中演示的示例查询。
样本索引
本节中的查询使用以下索引。此索引定义将 MongoDB Search 配置为执行以下操作：
自动索引集合中所有可动态索引的字段。
将
funding_rounds和funding_rounds.investments字段索引为 embeddedDocuments 类型。将以下字段存储在
mongot上：funding_rounds.investments.financial_orgfunding_rounds.investments.person
{ "mappings": { "dynamic": true, "fields": { "funding_rounds": { "dynamic": true, "fields": { "investments": [ { "dynamic": true, "storedSource": { "include": [ "financial_org", "person" ] }, "type": "embeddedDocuments" } ] }, "type": "embeddedDocuments" } } }}样本查询
以下查询使用 equals 操作符在 funding_rounds.founded_year 字段中搜索成立于 2005 年的公司，以检索投资明细，例如投资于这些公司的金融组织或个人。
db.companies.aggregate([ { "$search": { "returnStoredSource": true, "returnScope": { "path": "funding_rounds.investments" }, "hasAncestor": { "ancestorPath": "funding_rounds", "operator": { "equals": { "path": "funding_rounds.funded_year", "value": 2005 } } } } }])[ { financial_org: { name: 'Frazier Technology Ventures', permalink: 'frazier-technology-ventures' }, person: null }, { financial_org: { name: 'Trinity Ventures', permalink: 'trinity-ventures' }, person: null }, { financial_org: { name: 'Accel Partners', permalink: 'accel-partners' }, person: null }, { financial_org: null, person: { first_name: 'Mark', last_name: 'Pincus', permalink: 'mark-pincus' } }, { financial_org: null, person: { first_name: 'Reid', last_name: 'Hoffman', permalink: 'reid-hoffman' } }, { financial_org: { name: 'First Round Capital', permalink: 'first-round-capital' }, person: null }, { financial_org: null, person: { first_name: 'Ram', last_name: 'Shriram', permalink: 'ram-shriram' } }, { financial_org: null, person: { first_name: 'Mitch', last_name: 'Kapor', permalink: 'mitch-kapor' } }, { financial_org: null, person: { first_name: 'Ron', last_name: 'Conway', permalink: 'ron-conway' } }, { financial_org: null, person: { first_name: 'Silvio', last_name: 'Scaglia', permalink: 'silvio-scaglia' } }, { financial_org: { name: 'Shelter Capital Partners', permalink: 'shelter-capital-partners' }, person: null }, { financial_org: { name: 'First Round Capital', permalink: 'first-round-capital' }, person: null }, { financial_org: { name: 'Liberty Associated Partners', permalink: 'liberty-associated-partners' }, person: null }, { financial_org: { name: 'Rose Tech Ventures', permalink: 'rose-tech-ventures' }, person: null }, { financial_org: { name: 'First Round Capital', permalink: 'first-round-capital' }, person: null }, { financial_org: { name: 'Lead Dog Ventures', permalink: 'lead-dog-ventures' }, person: null }, { financial_org: { name: 'Accel Partners', permalink: 'accel-partners' }, person: null }, { financial_org: { name: 'Benchmark', permalink: 'benchmark-2' }, person: null }, { financial_org: { name: 'Sequoia Capital', permalink: 'sequoia-capital' }, person: null }, { financial_org: null, person: null }]