A foreign table is a schema objectthat records the metadata necessary for SQLstream s-Server to be able to access a table (or similar data structure) in a remote database. A foreign table can be used in SQL (both queries and updates) just like a local table.
The only option always required when defining a JDBC foreign table is TABLE_NAME (or OBJECT). For servers which support multiple schemas, the SCHEMA_NAME option can be specified at the table level to choose a schema other than the default. To use a foreign table, you first need to define server information for the external database.
### Defining a Foreign Table
When you define a foreign table, you
You can set these options when you declare a server, and override these options in a table definition.
| Name | Description | | --- | --- | | TABLE_NAME | Name of the remote table. |
Like all tables, foreign tables need to be created within schemas. The following code first creates and sets a schema called "MOCHI," then creates a foreign table called "regional_activity" which uses the server defined above and indicates a schema in the foreign database called "public" and a table in the foreign database called "regional_activity."
CREATE OR REPLACE SCHEMA "MOCHI" SET SCHEMA 'MOCHI'; CREATE OR REPLACE FOREIGN TABLE "regional_activity" SERVER "Postgres_DB" OPTIONS ( SCHEMA\_NAME 'public' --schema name in the foreign database TABLE\_NAME 'regional_activity' --table name in the foreign database ) DESCRIPTION 'per-city summary of suspicious activity';
See also IMPORT FOREIGN SCHEMA .