Datastax 驱动程序映射 ORDER BY ASC/DESC

Question

假设下一个 Cassandra ColumnFamily：

CREATE TABLE myTable (
    A text,
    B text,
    time timestamp,
    PRIMARY KEY ((A, B), time)
) WITH CLUSTERING ORDER BY (time ASC)
    AND bloom_filter_fp_chance = 0.01
    AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
    AND comment = ''
    AND compaction = {'min_threshold': '4', 'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32'}
    AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
    AND dclocal_read_repair_chance = 0.1
    AND default_time_to_live = 0
    AND gc_grace_seconds = 864000
    AND max_index_interval = 2048
    AND memtable_flush_period_in_ms = 0
    AND min_index_interval = 128
    AND read_repair_chance = 0.0
    AND speculative_retry = '99.0PERCENTILE';

我需要执行下一个 CQL 3 查询：

SELECT * FROM myTable WHERE A='aaaaa' AND B='bbbbb' ORDER BY time DESC

（在 CQL 控制台中工作正常）通过使用 Datastax 驱动程序映射 (cassandra-driver-mapping-2.1.6)。我的辅助器是下一个：

@Accessor
public interface myTableAccesor {  

    @Query("SELECT * FROM myTable WHERE A=:A AND B=:B ORDER BY time :order")
    Result<myTable> getAllByKey(@Param("A") String A, @Param("B") String B, @Param("order") String order);
}

但我得到下一个异常：

java.util.concurrent.ExecutionException: com.datastax.driver.core.exceptions.SyntaxError: line 1:136 missing EOF at ':' (...=:B ORDER BY time [:]order)

当我执行时：

myTableAccesor accessor = manager.createAccessor(myTableAccesor.class);

但是，LIMIT 情况：

@Query("SELECT * FROM myTable WHERE A=:A AND B=:B LIMIT :max")
        Result<myTable> getAllByKey(@Param("A") String A, @Param("B") String B, @Param("max") String max);

工作正常。

我认为问题与 String 类型有关（也许是某些 ' 字符？）但我不确定。有什么办法可以解决吗？

提前致谢。

Answer 1

不幸的是，像使用 LIMIT 一样，在准备好的语句（这是访问器使用的）中绑定到 ORDER BY 方向是无效的 CQL。作为解决方法，您可以创建两个单独的访问器：

@Query("SELECT * FROM myTable WHERE A=:A AND B=:B ORDER BY time DESC")
Result<myTable> getAllByKeyDesc(@Param("A") String A, @Param("B") String B);

@Query("SELECT * FROM myTable WHERE A=:A AND B=:B ORDER BY time ASC")
Result<myTable> getAllByKeyAsc(@Param("A") String A, @Param("B") String B);

Datastax 驱动程序映射 ORDER BY ASC/DESC

Datastax Driver Mapping ORDER BY ASC/DESC

mapping

cql

cassandra

datastax-java-driver