3.18. Foreign data wrappers
Foreign-data wrappers are objects used to consume data from different data sources, not necessarily another PostgreSQL database system. These different data sources can be CSV files, web services, or even database servers from different vendors.
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| Attributes | ||
|---|---|---|
| # | Field | Description |
| 1 | Handler function | A previously registered function that is called to retrieve the execution functions for foreign tables. The handler function must take no arguments and its return type must be |
| 2 | Validator function | A previously registered function that is called to check the generic options given to the foreign-data wrapper, as well as the options of the foreign servers, user mappings, and foreign tables that use the wrapper. |
| 3 | Options | The options of the foreign-data wrapper. The allowed names and values are specific to each wrapper and are validated by its validator function. |
References
Foreign-data wrapper DDL
https://www.postgresql.org/docs/current/sql-createforeigndatawrapper.html