Progress
Database Administration
Guide and Reference


Storage Design Overview

The storage design of a Progress Version 9 database is divided into a physical model and a logical model. You manipulate the physical storage model through 4GL, SQL-92, and database administration utility interfaces. Figure 1–2 shows how areas can be stored on and even span different file slices. Note that though an area’s extents can contain many disk files, an extent can only be associated with one storage area.

Figure 1–2: Physical Storage Model

The logical storage model can be manipulated through 4GL and SQL-92 interfaces. Logical database objects are described in the database schema and include tables, indexes, and sequences. You update these objects through 4GL and SQL-92 language statements. Figure 1–3 illustrates how logical objects can span physical extents.

Figure 1–3: Logical Storage Model

The following sections describe the three components of the Progress Version 9 storage model.


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