Python Azure Database ricks创建增量表异常：不存在事务日志

Question

我正在使用 Azure 数据砖，并且正在尝试创建一个增量表。

蟒蛇代码：

delta_save_path = "/mnt/ops/test/alerts"
try: 
  sqlContext.sql("CREATE TABLE ops.test_alerts USING DELTA LOCATION '" + delta_save_path + "'")
except Exception as e:
  print(str(e))

错误消息：

You are trying to create an external table `ops`.`test_alerts`
from `/mnt/ops/test/alerts` using Databricks Delta, but there is no transaction log present at
`/mnt/ops/test/alerts/_delta_log`. Check the upstream job to make sure that it is writing using
format("delta") and that the path is the root of the table.

我做错了什么？

Answer 1

delta_save_path = "/mnt/ops/test/alerts"

df = spark.read.format("csv").option("header", "false").load(delta_save_path)

df.write.format("delta").mode("overwrite").saveAsTable("ops.test_alerts")

Answer 2

当您想要从现有数据创建一个表时，您正在使用的语法。但是看起来您正在创建一个空表，所以在这种情况下您需要为您的表提供一个模式，就像这样(模式是虚构的):

CREATE TABLE ops.test_alerts (
  id int,
  metric_nam string,
  timestamp timestamp
) USING DELTA 
LOCATION '<some location>'

有关详细信息，请参阅CREATE TABLE留档