Tablestore:Summary and highlighting

Prerequisites

• An OTSClient instance is initialized. For more information, see Initialize an OTSClient instance.

• A data table is created and data is written to the data table. For more information, see Create data tables and Write data.

• A search index is created for the data table. For more information, see Create a search index.

Notes

• The query highlighting feature is available in Tablestore Node.js Software Development Kit (SDK) 5.5.0 and later. Ensure that you are using a compatible SDK version. For more information about the release history of the Node.js SDK, see Node.js SDK release history.

• When you use the query highlighting feature with a MatchQuery or MatchPhraseQuery, the search query may be highlighted by multiple pre-tags and post-tags.

• If a Text field uses maximum semantics tokenization, the query highlighting feature is not supported for MatchPhraseQuery.

• A search query might not be highlighted if sharding splits the query within the source text.

Parameters

Example

The following example uses a match query to retrieve rows in which the description field contains the tablestore term. The example encloses matched terms in the returned fragments with <b> and </b>. The description field is a Text field for which summary and highlighting is enabled.

client.search({
    tableName: "<TABLE_NAME>",
    indexName: "<SEARCH_INDEX_NAME>",
    searchQuery: {
        offset: 0,
        limit: 10, // To get only the row count without any specific data, set limit to 0. This prevents any rows from being returned.
        query: { // Set the query type to MatchQuery.
            queryType: TableStore.QueryType.MATCH_QUERY,
            query: {
                fieldName: "Col_Text", // Set the column to match.
                text: "hangzhou shanghai" // Set the value to match.
            }
        },
        highlight:{
            highlightEncoder:TableStore.HighlightEncoder.PLAIN_MODE,
            highlightParameters:[
                {
                    fieldName:"Col_Text",
                    preTag: "",
                    postTag: "",
                    fragmentsOrder: TableStore.HighlightFragmentOrder.TEXT_SEQUENCE,
                    fragmentSize: 20,
                    numberOfFragments: 3,
                }
                
            ],
        },
        getTotalCount: true // TotalCount in the results indicates the total number of rows in the table. The default value is false, which means the total count is not returned.
    },
    columnToGet: { // The columns to return. Valid values: RETURN_SPECIFIED (return custom columns), RETURN_ALL (return all columns), RETURN_ALL_FROM_INDEX (return all columns from the search index), and RETURN_NONE (return no columns).
        returnType: TableStore.ColumnReturnType.RETURN_ALL
    }
}, function (err, data) {
    if (err) {
        console.log('error:', err);
        return;
    }
    console.log('success:', JSON.stringify(data.rows, null, 2));
    printSearchHit(data.searchHits, "");
});


/**
 * Print the content of searchHits.
 * @param searchHits The search hits.
 * @param prefix The prefix to add for nested structures to print hierarchical information.
 */
function printSearchHit(searchHits, prefix) {
    TableStore.util.arrayEach(searchHits, function (searchHit) {
        if (searchHit.highlightResultItem != null) {
            console.log(prefix + "Highlight: \n");
            var strBuilder = ""
            for  (const [key,val]  of searchHit.highlightResultItem.highlightFields.entries()) {
                strBuilder += key + ":[";
                strBuilder += val.fragments.join(",") + "]\n";
                console.log(strBuilder);
            }
        }
        for  (const [key,val]  of searchHit.searchInnerHits.entries()) {
            console.log(prefix + "Path: " + key + "\n");
            console.log(prefix + "InnerHit: \n");
            printSearchHit(val.subSearchHits, prefix + "    ");
        }
    });
}

References

• For more information about the query highlighting feature, see Summary and highlighting.

• For more information about using the query highlighting feature with a nested field, see Nested query.