Unity Catalog with UniForm tables

UniForm tables are Delta tables with both Delta Lake and Iceberg metadata. UniForm tables can easily be read by Delta or Iceberg clients.

UniForm makes it easy for all engines to read Delta tables, even engines that only have Iceberg connectors and don't have Delta Lake connectors.

Read Delta Uniform tables via Iceberg REST Catalog

Delta Tables with Uniform enabled can be accessed via Iceberg REST Catalog. The Iceberg REST Catalog is served at http://127.0.0.1:8080/api/2.1/unity-catalog/iceberg/.

A pre-populated Delta Uniform table can be prepared by running cp -r etc/data/external/unity/default/tables/marksheet_uniform /tmp/marksheet_uniform.

Setting up REST Catalog with Apache Spark

The following is an example of the settings to configure OSS Apache Spark to read UniForm as Iceberg:

"spark.sql.extensions": "org.apache.iceberg.spark.extensions.IcebergSparkSessionExtensions",
"spark.sql.catalog.iceberg": "org.apache.iceberg.spark.SparkCatalog",
"spark.sql.catalog.iceberg.catalog-impl": "org.apache.iceberg.rest.RESTCatalog",
"spark.sql.catalog.iceberg.uri": "http://127.0.0.1:8080/api/2.1/unity-catalog/iceberg",
"spark.sql.catalog.iceberg.token": "not_used",

When querying Iceberg REST Catalog for Unity Catalog, tables are identified using the following pattern iceberg.<catalog-name>.<schema-name>.<table-name> (e.g. iceberg.unity.default.marksheet_uniform).