A database consists of physical data storage characteristics,
    such as a root file and storage area specifications; metadata
    definitions, such as tables and domains; and user data.

    By default, a database contains a single schema and no catalogs.
    If you specify the multischema attribute when creating your
    database, you can group the data definitions within one or more
    schemas within one or more catalogs. See the CREATE DATABASE for
    information on how to create a multischema database.

    When you create a database, you name it by specifying a file
    name and an optional repository path name in the CREATE DATABASE
    statement. You can supply a complete file specification, a
    partial file specification, or use system-supplied default
    values. You must use ASCII alphanumeric characters for the
    database name.

    To perform operations on a database, the database name is
    referenced through an attachment to that database called an
    alias. When you first refer to a database in SQL, you must
    indicate the source of data definitions for the database and the
    location of database files by declaring an alias. You can declare
    an alias using one of three statements:

    o  ATTACH

    o  CONNECT

    o  DECLARE ALIAS

    Choose a statement based on the interface that you are using
    (interactive SQL, SQL module language, or precompiled SQL) and
    your purpose (declaring a new alias or overriding the association
    between an alias and a database name). More information about
    aliases appears in Aliases.

    There are two ways to identify the source of data definitions:

    o  With a file specification

    o  With a repository path name (if the repository is installed on
       the system)

1  –  Oracle Rdb Attach Specifications

    When you first create a database, you give file specifications
    for the files that contain all database definitions (metadata)
    and user data stored in the database. You must use ASCII
    alphanumeric characters for the file specification name.

    You can also use a file specification whenever you refer to a
    database in the CONNECT and DECLARE ALIAS statements, although
    Oracle Rdb recommends that you always use a repository path name
    when the repository is installed.

    A full file specification includes:

    o  Network node name

    o  Device name

    o  Directory name or list

    o  File name

    o  File extension

    o  File version number

    Note that if you are specifying a database name for a remote
    database, all logical names/file specifications referenced
    will be evaluated on the remote node, not on the local node.
    Therefore, the necessary logical names/file specifications must
    exist on the remote node.

2  –  Repository Path Names

    Unless you use the PATHNAME argument in the CREATE DATABASE
    statement, SQL does not use the repository to store data
    definitions.

    If you specify the PATHNAME argument when you first create a
    database, SQL creates a path name that contains copies of data
    definitions for the database.

    Because SQL treats a path name like a string literal, you must
    enclose a path name in single quotation marks. You must use ASCII
    alphanumeric characters for the repository path name.

    When you issue an ATTACH or a DECLARE ALIAS statement, you can
    either specify the repository path name for that database (which
    in turn points to the physical database files) or directly name
    the physical database file specification.

    If you do not use the PATHNAME argument in the CREATE DATABASE
    statement, you cannot specify a path name in ATTACH or DECLARE
    ALIAS statements for that database unless you first issue an
    INTEGRATE statement. Oracle Rdb recommends that you always use
    a repository path name in CREATE DATABASE, ATTACH, and DECLARE
    ALIAS statements, and that you use the DICTIONARY IS REQUIRED
    clause to ensure that the two copies are the same.

    A repository path name can be a:

    o  Full path name, such as CDD$TOP.ELLINGSWORTH.SQL.PERSONNEL

    o  Relative path name

       A relative path name consists of the portion of the full
       path name that follows the current default repository
       node. For example, assume that you used the SET DICTIONARY
       command to set the current repository directory to
       CDD$TOP.ELLINGSWORTH.SQL. Now you can use the relative
       path name PERSONNEL in place of the full path name
       CDD$TOP.ELLINGSWORTH.SQL.PERSONNEL. By default, SQL sets
       the current repository node to the path name defined by the
       CDD$DEFAULT logical name. See the SET for the description
       of the SET DICTIONARY statement. See also Using Oracle
       CDD/Repository on OpenVMS Systems for more detail on
       repository path names.

    o  Logical name for a full or relative path name

    Some Oracle Rdb features are not fully supported by all versions
    of the repository. If you attach by path name and attempt
    to create, modify, or delete objects not fully supported by
    the repository, you may receive an error or informational
    message. See the Oracle Rdb Release Notes for information about
    compatibility of Oracle Rdb features with the different versions
    of the repository.