anchor.diff:  AUTOCOMMIT must be turned ON (the default) for the session.
   
   ```
  -CREATE [schema-class] SCHEMA schema-clause
  +CREATE [schema-class] SCHEMA [IF NOT EXISTS] schema-clause
   
   schema-class is:
      [ PRIVATE | SHARED ]
  
positive.code: any database user may add objects to the schema (SHARED). The default class is PRIVATE.
  +
  NOTE: Schemas created in {project-name} Release 0.9 or earlier are SHARED schemas.
  
  * `_schema-name_`
  +
  
negative.code: * `_schema-name_`
  +
  is the name of the schema to delete.
  
  * `IF EXISTS`
  +
  drops the schema if it exists. If omitted, an error is raised if the schema doesn't exist.
  
  * `RESTRICT`
  +
  