这是将在cassandra数据库上创建表的实体类 .
@Table
public class Log {
@PrimaryKeyColumn(ordinal = 0, type = PrimaryKeyType.PARTITIONED)
private LocalDate date; //partition key
@PrimaryKeyColumn(ordinal = 1, type = PrimaryKeyType.PARTITIONED)
private String name; //partition key
@PrimaryKeyColumn(ordinal = 2, type = PrimaryKeyType.PARTITIONED)
private String catagory; //partition key
@PrimaryKeyColumn(ordinal = 3, type = PrimaryKeyType.CLUSTERED)
private String timeStamp; //clustering column
private String type;
private String description;
}
主键是（（日期，名称，类别），时间戳）其中（日期，名称，类别）是分区键，时间戳是聚类列 .
这是执行插入时的预期数据
Date | name | category| timestamp | type | description |
------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.732 | short | desc1 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.735 | long | desc2 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.736 | short | desc3 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.738 | long | desc4 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.740 | short | desc5 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.741 | short | desc6 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.743 | long | desc7 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.745 | short | desc8 |
-------------------------------------------------------------------
当使用CrudRepository的save方法执行插入时，下面的数据存储在Cassandra中 . 有些行是upserted . 缺少描述desc3，desc5的行 .
Date | name | category| timestamp | type | description |
------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.732 | short | desc1 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.735 | long | desc2 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.738 | long | desc4 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.741 | short | desc6 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.743 | long | desc7 |
-------------------------------------------------------------------
2017-10-11 | 201 | General | 19:51:18.745 | short | desc8 |
-------------------------------------------------------------------
正在使用的Repo是一个扩展CrudRepository的接口，如下所示：
public interface LogRepo extends CrudRepository<Log , LocalDate>
{
...
}
执行的插入代码如下：
for(...){
..
logRepo.save(log); //each object is saved
..
}
由于群集列是时间戳，并且在这种情况下是唯一的，因此理想情况下不应该对行进行插值 . 请告知是否有任何遗漏，以避免记录 .