dependency relationships between database objects and shared objects,
such as roles. This information allows
to ensure that those objects are
unreferenced before attempting to delete them.
which performs a similar function for dependencies involving objects
within a single database.
Unlike most system catalogs,
is shared across all databases of a cluster: there is only one
per cluster, not
one per database.
The OID of the database the dependent object is in, or zero for a shared object
The OID of the system catalog the dependent object is in
The OID of the specific dependent object
For a table column, this is the column number (the
The OID of the system catalog the referenced object is in (must be a shared catalog)
The OID of the specific referenced object
A code defining the specific semantics of this dependency relationship; see text
In all cases, a
entry indicates that
the referenced object cannot be dropped without also dropping the dependent
object. However, there are several subflavors identified by
The referenced object (which must be a role) is the owner of the dependent object.
The referenced object (which must be a role) is mentioned in the ACL (access control list, i.e., privileges list) of the dependent object. (A
SHARED_DEPENDENCY_ACLentry is not made for the owner of the object, since the owner will have a
The referenced object (which must be a role) is mentioned as the target of a dependent policy object.
There is no dependent object; this type of entry is a signal that the system itself depends on the referenced object, and so that object must never be deleted. Entries of this type are created only by
initdb. The columns for the dependent object contain zeroes.
The referenced object (which must be a tablespace) is mentioned as the tablespace for a relation that doesn't have storage.
Other dependency flavors might be needed in future. Note in particular that the current definition only supports roles and tablespaces as referenced objects.