Atlas Vector Search

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Overview
Atlas Vector Search 索引
Vector Search Aggregation Stage
Atlas Search查询示例
Basic Vector Search Query
Vector Search Score
Vector Search Options

Overview

In this guide, you can learn how to perform searches on your documents by using the Atlas Vector Search feature. The PHP library allows you to perform Atlas Vector Search queries by using the 聚合构建器.

注意

部署兼容性

You can use the Atlas Vector Search feature only when you connect to MongoDB Atlas clusters. This feature is not available for self-managed deployments.

To learn more about Atlas Vector Search, see the Atlas Vector Search Overview. The Atlas Vector Search implementation for the PHP library internally uses the $vectorSearch aggregation operator to perform queries. To learn more about this operator, see the $vectorSearch reference in the Atlas documentation.

注意

Atlas Search

To perform advanced full-text search on your documents, you can use the Atlas Search API. To learn about this feature, see the Atlas Search guide.

Atlas Vector Search 索引

Before you can perform Atlas Vector Search queries, you must create an Atlas Vector Search index on your collection. To learn more about creating this index type, see the Atlas Search 索引 guide.

Vector Search Aggregation Stage

将以下类导入到应用程序中，以使用聚合构建器执行Atlas Search查询：

use MongoDB\Builder\Stage;

要在聚合管道中创建 $vectorSearch 阶段，请执行以下操作：

创建一个大量来存储管道阶段。
Call the Stage::vectorSearch() method to create the Atlas Vector Search stage.
Within the body of the vectorSearch() method, specify the criteria for your vector query.

以下代码演示了用于构建基本Atlas Search查询的模板：

$pipeline = [
    Stage::vectorSearch(
        /* Atlas Vector Search query specifications
        index: '<index name>',
        path: '<path to embeddings>', ...*/
    ),
];

You must pass the following parameters to the vectorSearch() method:

Parameter	类型	说明
`index`	`string`	Name of the vector search index
`path`	`array` 或 `string`	Field that stores vector embeddings
`queryVector`	`array`	Vector representation of your query
`limit`	`int`	Number of results to return

Atlas Search查询示例

In this section, you can learn how to perform Atlas Vector Search queries by using the Aggregation Builder. The examples in this section use sample data from the sample_mflix.embedded_movies collection.

注意

Query Vector Length

For demonstrative purposes, the examples in this section use sample query vectors that contain very few elements, compared to the query vector you might use in a runnable application. To view an example that contains the full-length query vector, see the Atlas Vector Search Quick Start and select PHP from the Select your language dropdown in the upper-right corner of the page.

Basic Vector Search Query

The following code performs an Atlas Vector Search query on the plot_embedding vector field:

$pipeline = [
    Stage::vectorSearch(
        index: 'vector',
        path: 'plot_embedding',
        queryVector: [-0.0016261312, -0.028070757, -0.011342932],
        numCandidates: 150,
        limit: 5,
    ),
    Stage::project(
        _id: 0,
        title: 1,
    ),
];
$cursor = $collection->aggregate($pipeline);
foreach ($cursor as $doc) {
    echo json_encode($doc), PHP_EOL;
}

{"title":"Thrill Seekers"}
{"title":"About Time"}
{"title":"Timecop"}
// Results truncated

Vector Search Score

The following code performs the same query as in the preceding example, but outputs only the title field and vectorSearchScore meta field, which describes how well the document matches the query vector:

$pipeline = [
    Stage::vectorSearch(
        index: 'vector',
        path: 'plot_embedding',
        queryVector: [-0.0016261312, -0.028070757, -0.011342932],
        numCandidates: 150,
        limit: 5,
    ),
    Stage::project(
        _id: 0,
        title: 1,
        score: ['$meta' => 'vectorSearchScore'],
    ),
];
$cursor = $collection->aggregate($pipeline);
foreach ($cursor as $doc) {
    echo json_encode($doc), PHP_EOL;
}

{"title":"Thrill Seekers","score":0.927734375}
{"title":"About Time","score":0.925750732421875}
{"title":"Timecop","score":0.9241180419921875}
// Results truncated

Vector Search Options

You can use the vectorSearch() method to perform many types of Atlas Vector Search queries. Depending on your desired query, you can pass the following optional parameters to vectorSearch():

可选参数	类型	说明	默认值
`exact`	`bool`	Specifies whether to run an Exact Nearest Neighbor (`true`) or Approximate Nearest Neighbor (`false`) search	`false`
`filter`	`QueryInterface` 或 `array`	Specifies a pre-filter for documents to search on	no filtering
`numCandidates`	`int` 或 `null`	Specifies the number of nearest neighbors to use during the search	`null`

$vectorSearch要学习；了解有关这些参数的更多信息，请参阅Atlas文档中操作符参考的字段部分。

后退

Atlas Search

来年

索引