You can use prefix query to query data that matches a specified prefix. If the type of a field is TEXT, Tablestore tokenizes the string and matches tokens by using the specified prefix.

Prerequisites

  • The OTSClient instance is initialized. For more information, see Initialization.
  • A data table is created, and data is written to the table.
  • A search index is created for the table. For more information, see Create search indexes.

Parameters

Parameter Description
field_name The name of the column used to match the query conditions.
prefix The prefix.

If the field used to match the query conditions is a TEXT field, the field values are tokenized. A row meets the query conditions when the tokenized value of the specified field contains at least one term that contains the specified prefix.

query The type of the query. Set the query type to PrefixQuery.
table_name The name of the table.
index_name The name of the search index.
limit The maximum number of rows that the current query returns.

To query the number of matched rows without detailed data, you can set limit to 0. In this case, Tablestore returns the number of matched rows without data from the table.

get_total_count Specifies whether to return the total number of rows that match the query conditions. By default, this parameter is set to False, which indicates that the total number of rows that match the query conditions is not returned.

Query performance is affected when this parameter is set to True.

columns_to_get Specifies whether to return all columns of each matched row. You can configure return_type and column_names for this parameter.
  • If you set return_type to ColumnReturnType.SPECIFIED, you can use column_names to specify the columns to return.
  • If you set return_type to ColumnReturnType.ALL, all columns are returned.
  • If you set return_type to ColumnReturnType.NONE, only the primary key columns are returned.

Examples

Use prefix query to query the rows in which the values of the k columns are prefixed with 'key00'.

  • Perform prefix query by using Tablestore SDK for Python V5.2.1 or later
    By default, if you use Tablestore SDK for Python V5.2.1 or later to perform a prefix query, SearchResponse objects are returned. The following code provides a request sample:
    query = PrefixQuery('k', 'key00')
    search_response = client.search(
        table_name, index_name, 
        SearchQuery(query, limit=100, get_total_count=True), 
        ColumnsToGet(return_type=ColumnReturnType.ALL)
    )
    You can use the following sample request to return results of the Tuple type:
    query = PrefixQuery('k', 'key00')
    rows, next_token, total_count, is_all_succeed, agg_results, group_by_results = client.search(
        table_name, index_name, 
        SearchQuery(query, limit=100, get_total_count=True), 
        ColumnsToGet(return_type=ColumnReturnType.ALL)
    ).v1_response()
  • Perform prefix query by using Tablestore SDK for Python of a version earlier than 5.2.1

    By default, if you use Tablestore SDK for Python of a version earlier than 5.2.1 to perform a prefix query, results of the Tuple type are returned. The following code provides a request sample:

    query = PrefixQuery('k', 'key00')
    rows, next_token, total_count, is_all_succeed = client.search(
        table_name, index_name, 
        SearchQuery(query, limit=100, get_total_count=True), 
        ColumnsToGet(return_type=ColumnReturnType.ALL)
    )