What is a database meta-schema? (4db)

A database meta-schema file is the central repository of a database's meta-data; information about the tables, columns, and relations, and default values of a relational database. Information from the database meta-schema file is used by Genero Studio Form Designer, Business Application Modeling, and Code Editor.

4db and 4dbx files

There are two types of database meta-schema files used by Genero Studio.

4db: Used in standard Genero Studio projects.
4dbx: Used in code-generated projects in Business Application Modeling. It includes special features for application generation such as a table for managing serial columns.

When is it used?

A database meta-schema file is required when you use Genero Studio to:

Examine the structure of a tables, columns, and other attributes.
Create a Genero Studio form definition based on a database table.
Generate application code.

The database meta-schema is not used by Genero Studio when an application is executed. Genero Studio uses the Genero runtime system and the specific database client software to access any databases referenced in a Genero application.

Meta-schema creation and maintenance

Database meta data can be extracted from a relational database into a meta-schema file, or it can be based on an existing database schema file.

It is important that the database meta-schema file match the current structure of the database itself. If changes are made in the database structure, any database meta-schema files that describe the database must also be updated.

Meta-schema Manager includes options to create and update a database based on meta-schema file changes.

GSTSCHEMANAMES

Set the GSTSCHEMANAMES environment variable to make meta-schemas available to all projects.