# pg_shdescription

The `pg_shdescription` system catalog table stores optional descriptions (comments) for shared database objects. Descriptions can be manipulated with the `COMMENT` command and viewed with `psql`’s `\d` meta-commands. See also [pg_description](./pg_description.md), which performs a similar function for descriptions involving objects within a single database. Unlike most system catalogs, `pg_shdescription` is shared across all databases of a OushuDB system: there is only one copy of `pg_shdescription` per system, not one per database.

Table 1. pg_catalog.pg_shdescription

| column        | type | references            | description                                                  |
| :------------ | :--- | :-------------------- | :----------------------------------------------------------- |
| `objoid`      | oid  | any OID column        | The OID of the object this description pertains to.          |
| `classoid`    | oid  | pg_class_internal.oid | The OID of the system catalog this object appears in         |
| `description` | text |                       | Arbitrary text that serves as the description of this object. |