Data Definition Language (DDL) Reference Manual (G06.24+)

Introduction to DDL
Data Definition Language (DDL) Reference Manual—426798-002
1-4
Creating a Dictionary
other objects, and so forth. You can, if you choose, modify the supplied queries or
write your own.
Creating a Dictionary
A DDL dictionary is a database consisting of 14 prenamed and predefined files.
Because the files have fixed names, you can have only one dictionary on any
subvolume. A DDL data dictionary can be created either by running the DDL compiler
or by running Pathmaker, a NonStop™ Transaction Services/MP (NonStop™ TS/MP)
application systems generator.
When you run the DDL compiler, you must open the dictionary with the DICT or DICTN
command. This command creates a dictionary, if one does not already exist, or opens
an existing dictionary. You can pass the DICT or DICTN command to the compiler as a
parameter in the DDL run command.
When you add a Pathmaker project, The Pathmaker program creates a DDL dictionary
for you. The DDL dictionary the Pathmaker program creates is part of a larger
database that contains application design information. The Pathmaker program enters
application design information into the dictionary.
Both Pathmaker dictionaries and dictionaries created from the DDL compiler can be
written to by more than one user at the same time.
Once a dictionary is created, you can enter object definitions into it. If you have a lot of
complex definitions, you probably want to present them in a source schema EDIT file
rather than entering them interactively.
The source schema statements can be submitted to DDL as an input file in a
noninteractive session or submitted with a SOURCE command in an interactive
session. (You can also enter statements directly in an interactive session.) In each
case, DDL compiles the object definition statements and, if a dictionary is open, writes
the objects to the dictionary.
Unless suppressed by a NOLIST command, DDL automatically produces a compiler
listing. By default, the listing is sent to the home terminal of the DDL process. You can
specify a different listing destination in the OUT run option of the DDL run command or
in an OUT command.
Note that a DDL dictionary is not actively integrated with the database files or source
code it describes. If you change a dictionary, DDL does not automatically change the
associated database or source code. Conversely, if you change a database or source
code directly, the associated dictionary is not affected.
Figure 1-2 on page 1-5 illustrates the following steps for building a schema and
compiling it into a dictionary:
1. Run a text editor program and enter DDL statements and, optionally, DDL
commands into an EDIT file. This file is your source schema.