<< Click to Display Table of Contents >>

Data Modeling

Top Previous Next

Normally, data modeling requires the use of a CASE tool. These huge software products are come with many features and full functionality. Consider the following most important components:

A data dictionary stores information about entities and relations. Because the dictionary is independent of the application database, it can be termed an offline dictionary.

A diagramming tool shows both logical and physical ER models. You can change properties using object context menus (right-click-menu, object inspector, ...) or use the drag and drop mechanism. In the same manner, the tool can create or delete entity definitions.

A DDL script generator produces the complete SQL script for creating a new database schema or modifying an existing one. Most systems support multiple target databases.

A reporting component generates printable documentation about the data model.

The use of a CASE tool has always proved useful

If a CASE tool is already available.

As a part of database design, i.e. the phase before the first creation of the physical database.

For very large database applications with hundreds of tables and many programmers sharing the work.

Oracle Developer supports the generation of Oracle Forms front ends, Oracle Reports and Oracle Web Applications from Oracle Designer information.

Sometimes you might catch yourself thinking that using a CASE tool is too cumbersome

In the process of application development your development database should already contain some stock or sample data. If the CASE tool does not support the automatic replication of the database structure in the CASE dictionary, you must decide between

o

Performing structure changes twice, i.e. applying all modifications to both the CASE tool and the physical database or

o

Recreating the physical database with empty tables. Existing stock or sample data will be lost.

Having to modify both the CASE information and the database itself means doubling the effort needed. The model must always be kept in synch with the database structure.

Purchasing a CASE tool is an expensive investment.

KeepTool offers a lean alternative to bulky CASE tools. Our concept is to associate the CASE data dictionary with the physical database dictionary. Data model changes are directly produced from changes to the database structure. There is no need for a separate design tool, because you have easy-to-use tools to survey the state of the existing database.

KeepTool ER Diagrammer scans the existing database tables and relationships. In a few moments, you have a ready-to-use E/R diagram.

Database schema modifications can be done using Hora. ER Diagrammer allows many of these operations by letting you right-click on the table representations.

The following context operations are available:

02_Table

Table

Creates a new table

 

Add column ...

Adds column to table

 

Add Foreign Key

Adds foreign key relation to another table

 

Add Primary Key, Unique, Index ...

Creates primary key, unique constraint or index

 

Drop Foreign Key

Drops a foreign-key relationship

 

Shape Color ...

Changes the color of the table shape