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query()

A MilvusClient interface. This method filters entities by a boolean expression. Note that the order of the returned entities can not be guaranteed.

R<QueryResponse> query(QuerySimpleParam requestParam);

QuerySimpleParam

Use the QuerySimpleParam.Builder to construct a QuerySimpleParam object.

import io.milvus.param.highlevel.dml.QuerySimpleParam;
QuerySimpleParam.Builder builder = QuerySimpleParam.newBuilder();

Methods of QuerySimpleParam.Builder:

MethodDescriptionParameters
withCollectionName(String collectionName)Sets the name of the target collection.
The value cannot be empty or null.
collectionName: Name of the collection against which the query is conducted.
withOutputFields(List<String> outputFields)Sets the names of the fields to return. If this value is set, the query result contains the values of these fields.outputFields: Fields to include in the query result.
withFilter(String filter)Sets an expression to filter entities. For more information, refer to this doc.filter: A boolean expression to filter entities.
withOffset(Long offset)Sets a position prior to which entities are to ignore in the query.offset: A position prior to which entities are to ignore.
withLimit(Long limit)Sets the number or entities to return.
The value should be 0 or a positive integer.
The value defaults to 0, which lifts the limits on the number of entities to return.
limit: Number of entities to return.
withConsistencyLevel(ConsistencyLevelEnum consistencyLevel)Sets the consistency level of the collection to query against. If not specified, the default consistency level is to be used. For details, please refer to ConsistencyLevelEnum in Misc.consistencyLevel: The consistency level of the collection to query against.
build()Constructs a QuerySimpleParam object.N/A

The QuerySimpleParam.Builder.build() method can throw the following exceptions:

  • ParamException is raised if the parameter is invalid.

Returns

This method catches all the exceptions and returns an R<QueryResponse> object.

  • If the API fails on the server side, it returns the error code and message from the server.
  • If the API fails by RPC exception, it returns R.Status.Unknow and the error message of the exception.
  • If the API succeeds, it returns valid QueryResponse held by the R template.

Example

import io.milvus.param.*;
import io.milvus.response.QueryResultsWrapper;
import io.milvus.response.FieldDataWrapper;
import io.milvus.grpc.QueryResults;

QuerySimpleParam querySimpleParam = QuerySimpleParam.newBuilder()
        .withCollectionName(COLLECTION_NAME)
        .withOutFields(Lists.newArrayList("*"))
        .withFilter(filter)
        .withLimit(100L)
        .withOffset(0L)
        .build();
R<QueryResponse> response = client.query(param)
if (response.getStatus() != R.Status.Success.getCode()) {
    System.out.println(response.getMessage());
}

for (QueryResultsWrapper.RowRecord rowRecord : response.getData().getRowRecords()) {
    System.out.println(rowRecord);
}