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CollectionSchema

Addedv2.3.xModifiedv3.0.x

A CollectionSchema instance represents the schema of a collection. A schema sketches the structure of a collection.

io.milvus.v2.service.collection.request.CreateCollectionReq.CollectionSchema

Constructor​

Constructs the schema of a collection by defining fields, data types, and other parameters.

CreateCollectionReq.CollectionSchema.builder()
    .fieldSchemaList(List<CreateCollectionReq.FieldSchema> fieldSchemaList)
    .structFields(List<CreateCollectionReq.StructFieldSchema> structFields)
    .enableDynamicField(boolean enableDynamicField)
    .functionList(List<CreateCollectionReq.Function> functionList)
    .externalSource(String externalSource)
    .externalSpec(JsonObject externalSpec)
    .build();

BUILDER METHODS:

  • fieldSchemaList(List<CreateCollectionReq.FieldSchema> fieldSchemaList) -

    A list of FieldSchema objects that define the fields in the collection schema. A field schema represents and contains metadata for a single field, while CollectionSchema ties together a list of FieldSchema objects to define the full schema.

  • structFields(List<CreateCollectionReq.StructFieldSchema> structFields) -

    A list of struct fields (nested-object fields) for the schema. Use this when the collection contains fields whose values are themselves structured records.

  • enableDynamicField(boolean enableDynamicField) -

    When set to true, enables a hidden dynamic field ($meta) so inserts can carry arbitrary key-value attributes outside the declared schema. Default: false.

  • functionList(List<CreateCollectionReq.Function> functionList) -

    Attaches functions (e.g., BM25, JSON-path extraction) that derive values from existing fields at insert time. Each Function declares its inputs, outputs, and parameters.

  • externalSource(String externalSource) -

    Identifies the external source (e.g., a S3 bucket, a Lakehouse table) bound to this collection. Pairs with externalSpec to define an external collection that refreshes from outside Milvus.

  • externalSpec(JsonObject externalSpec) -

    Specification for the external source — typically JSON describing connection details and refresh policy. Used together with externalSource.

RETURN TYPE:

CollectionSchema

RETURNS:

A CollectionSchema object.

EXCEPTIONS:

  • MilvusClientExceptions

    This exception will be raised when any error occurs during this operation.

Example​

import io.milvus.v2.common.DataType;
import io.milvus.v2.service.collection.request.AddFieldReq;
import io.milvus.v2.service.collection.request.CreateCollectionReq;

// define a Collection Schema
CreateCollectionReq.CollectionSchema collectionSchema = client.createSchema();
// add two fields, id and vector
collectionSchema.addField(AddFieldReq.builder().fieldName("id").dataType(DataType.Int64).isPrimaryKey(Boolean.TRUE).autoID(Boolean.FALSE).description("id").build());
collectionSchema.addField(AddFieldReq.builder().fieldName("vector").dataType(DataType.FloatVector).dimension(dim).build());

Methods​

The following are the methods of the CollectionSchema class: