Access a JDBC external table

An external data source is mapped to a Catalog in the Lindorm compute engine. The Catalog acts as an identifier for the data source. You must specify a custom name for the Catalog. The following table describes the parameters for a Spark SQL job that uses hello_jdbc as the Catalog name.

Configure and submit Spark jobs for an external data source using one of the following methods. Then, use Spark SQL to access the data source.

• JDBC developer guide

• Best practices for developing JAR jobs

• Developing Python Jobs

• Example 1: Read data from the external JDBC table `db0.mysql_tbl0`, join the data with the Hive table `hive_tbl0`, and write the result to the Hive table `hive_tbl1`.

  INSERT INTO spark_catalog.default.hive_tbl1
  SELECT A.col0, A.col1, A.col2, B.col1
  FROM hello_jdbc.db0.mysql_tbl0 A JOIN spark_catalog.default.hive_tbl0 B
  ON A.col0 = B.col0;

• Example 2: Filter the Hive table `hive_tbl1` and write the result to the external JDBC table `db0.mysql_tbl1`.

  INSERT INTO hello_jdbc.db0.mysql_tbl1
  SELECT col0, col1, col2
  FROM spark_catalog.default.hive_tbl1
  WHERE col0 > 12345;