# Data Dictionary

Data Dictionary Objects |

PxPlus includes a set of predefined data dictionary objects for working with the data dictionary. These objects, which are designed for use under PxPlus Object Oriented Programming (OOP), are described in this section.

## Maintenance Objects

The Database and PVXDb objects allow you to create and modify the PxPlus data dictionary at both the logical (providex.ddf and providex.dde) and physical file level. These provide the same functionality programmatically that is available via the Data Dictionary Maintenance interface:

| Database | Accesses providex.ddf and providex.dde files, returning table, column and index information for the specified table name (table).
| PVXDb | Accesses internal definitions that are embedded in a file using a file handle (fh) to reference each PVX data file.

For a list of the methods belonging to these objects, see Database and PVXDb Objects. These, in turn, delegate functionality to a level of Subordinate Maintenance Objects.

For sample programs, see Maintenance Examples.

## Database Interface Object

The following object provides a database-independent interface for retrieving and updating table information:

| Db_Manager | Accesses table information for retrieval and update between an external database and the providex.ddf and providex.dde files.

For information about this object, see Db_Manager Object.

For sample programs, see Database Interface Examples.