sys.external_tables (Transact-SQL)

Applies to: SQL Server 2016 (13.x) and later Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)

Contains a row for each external table in the current database.

Column Name	Data Type	Description	Range
<inherited columns>		For a list of columns that this view inherits, see sys.objects (Transact-SQL).
max_column_id_used	int	Maximum column ID ever used for this table.
uses_ansi_nulls	bit	Table was created with the SET ANSI_NULLS database option ON.
data_source_id	int	Object ID for the external data source.
file_format_id	int	For external tables over a HADOOP external data source, this is the Object ID for the external file format.
location	nvarchar(4000)	For external tables over a HADOOP external data source, this is the path of the external data in HDFS.
reject_type	tinyint	For external tables over a HADOOP external data source, this is the way rejected rows are counted when querying external data.	VALUE - the number of rejected rows. PERCENTAGE - the percentage of rejected rows.
reject_value	float	For external tables over a HADOOP external data source: For reject_type = value, this is the number of row rejections to allow before failing the query. For reject_type = percentage, this is the percentage of row rejections to allow before failing the query.
reject_sample_value	int	For reject_type = percentage, this is the number of rows to load, either successfully or unsuccessfully, before calculating the percentage of rejected rows.	NULL if reject_type = VALUE.
distribution_type	int	For external tables over a SHARD_MAP_MANAGER external data source, this is the data distribution of the rows across the underlying base tables.	0 - Sharded 1 - Replicated 2 - Round robin
distribution_desc	nvarchar(120)	For external tables over a SHARD_MAP_MANAGER external data source, this is the distribution type displayed as a string.
sharding_column_id	int	For external tables over a SHARD_MAP_MANAGER external data source and a sharded distribution, this is the column ID of the column that contains the sharding key values.
remote_schema_name	sysname	For external tables over a SHARD_MAP_MANAGER external data source, this is the schema where the base table is located on the remote databases (if different from the schema where the external table is defined).
remote_object_name	sysname	For external tables over a SHARD_MAP_MANAGER external data source, this is the name of the base table on the remote databases (if different from the name of the external table).

Permissions

The visibility of the metadata in catalog views is limited to securables that a user either owns or on which the user has been granted some permission. For more information, see Metadata Visibility Configuration.

See Also

sys.external_file_formats (Transact-SQL)
sys.external_data_sources (Transact-SQL)
CREATE EXTERNAL TABLE (Transact-SQL)