Question

我尝试在Cassandra 3上实现触发器，通过实现

来捕获特定表上的删除操作

 public Collection<Mutation> augment(Partition partition)

ITrigger界面上的

但我无法区分更新和删除操作。

我怎样才能发现该操作是删除操作？

Answer 1

以下是捕捉所有类型删除的方法

public Collection<Mutation> augment(Partition partition) {
    if(partition.partitionLevelDeletion().isLive()) {
        UnfilteredRowIterator it = partition.unfilteredIterator();
        while (it.hasNext()) {
            Unfiltered unfiltered = it.next();
            switch (unfiltered.kind()) {
                case ROW:
                    Row row = (Row) unfiltered;

                    if (!row.deletion().isLive()) {
                        // Row deletion
                    }

                    for (Cell cell : row.cell()) {
                        if (cell.isTombstone() {
                            // Cell deletion
                        } else {
                            // Insert or Update
                        }  
                    }
                    break;
                case RANGE_TOMBSTONE_MARKER:
                    // Range Deletion
                    break;
            }
        }
    } else {
        // Partition Level Deletion
    }
}

我们说我们有桌子：

CREATE TABLE kv (
    pk int,
    ck int,
    d int,
    PRIMARY KEY (pk, ck)
);

此处pk是分区键，ck是群集键

分区级别删除：

DELETE from kv WHERE pk = 1;

范围删除：

DELETE from kv WHERE pk = 1 AND ck > 10;

行删除：

 DELETE from kv WHERE pk = 1 AND ck = 10;

细胞删除：

DELETE d from kv WHERE pk = 1 AND ck = 10;

Cassandra 3触发删除操作

1 个答案: