Data Definition Language (DDL) Reference Manual

Introduction to DDL

Data Definition Language (DDL) Reference Manual—529431-004

1-4

Using DDL Definitions

You use DDL statements to define, modify, delete, and display data in a dictionary.

You use DDL commands to create and open DDL dictionaries and to generate files

containing FUP commands, data definition source code in different languages, and

report specifications. You can use DDL to perform these functions:

•

Create a schema

A DDL schema is composed of DDL statements that define the DDL objects. You

can create a schema in an EDIT file and submit the file (called the schema file) to

the DDL compiler, or you can run the DDL compiler and enter the definitions

interactively.

•

Create a dictionary

A dictionary is a DDL database that contains the objects defined in a schema.

When you run the DDL compiler to compile the schema, you can direct the DDL

compiler to store the object definitions from the schema in the open dictionary.

•

Create a database

You can direct the DDL compiler to generate FUP commands from the record

definitions in a schema or dictionary and to write these commands to an EDIT file.

You can edit the commands, if needed, and then submit the command file to FUP

to create your database files.

•

Generate source code for programming languages

Figure 1-1. DDL Compiler Overview

VST001.vsd

Source

File

Dictionary

PascalTAL

FORTRAN

FUP

COBOL TACL

DDL

Listing Report

5> DDL

Compiler

Output

Generator

DDL