外部表External tables

外部表是引用存储在 Azure 数据资源管理器数据库外部的数据的 Kusto 架构实体。An external table is a Kusto schema entity that references data stored outside the Azure Data Explorer database.

类似,外部表具有明确定义的架构(列名称和数据类型对的已排序列表)。Similar to tables, an external table has a well-defined schema (an ordered list of column name and data type pairs). 与表不同,数据是在群集外部进行存储和管理的。Unlike tables, data is stored and managed outside the cluster. 大多数情况下,数据以某些标准格式(例如 CSV、Parquet、Avro)存储,而不是由 Azure 数据资源管理器引入。Most commonly the data is stored in some standard format such as CSV, Parquet, Avro, and isn't ingested by Azure Data Explorer.

外部表只创建一次。An external table is created once. 请参阅以下命令创建外部表:See the following commands for external table creation:

可使用 external_table() 函数按外部表名称引用外部表。An external table can be referenced by its name using the external_table() function.

说明Notes

  • 外部表名称:External table names:
    • 区分大小写。Case-sensitive.
    • 不能与 Kusto 表名重叠。Can’t overlap with Kusto table names.
    • 需遵循实体名称的规则。Follow the rules for entity names.
  • 每个数据库的外部表数量上限为 1,000。Maximum limit of external tables per database is 1,000.
  • Kusto 支持导出连续导出到外部表,以及查询外部表Kusto supports export and continuous export to an external table, and querying external tables.
  • 数据清除未应用于外部表。Data purge isn't applied on external tables. 记录永远不会从外部表中删除。Records are never deleted from external tables.