A namespace is the structure underlying SQL92 schemas: each namespace
   can have a separate collection of relations, types, etc without name
   conflicts.
  
Table 3-21. pg_namespace Columns
| Name | Type | References | Description | 
|---|
| nspname | name |  | Name of the namespace | 
| nspowner | int4 | pg_shadow.usesysid | Owner (creator) of the namespace | 
| nspacl | aclitem[] |  | Access permissions |