Chapter 2 Physical Data Model Basics
The PDM includes different types of diagrams, with their objects:
| Object | Tool | Description |
|---|---|---|
| Table | 
|
Collection of rows (records) that have associated columns (fields) |
| Column | — | Data structure that contains an individual data item within a row (record), model equivalent of a database field. |
| Key | — | Column or columns whose values uniquely identify each row in a table. A key can be designated as a primary or alternate key |
| Primary key | — | Column or columns whose values uniquely identify each row in a table, and are designated as the primary identifier of each row in the table |
| Alternate key | — | Column or columns whose values uniquely identify each row in a table, and which is not a primary key |
| Foreign key | — | Column or columns whose values depend on and migrate from a primary or alternate key in another table. |
| Index | — | Data structure associated with one or more columns in a table, in which the column values are ordered in such a way as to speed up access to data |
| Reference | 
|
Link between a primary or an alternate key in a parent table, and a foreign key of a child table. Depending on its selected properties, a reference can also link columns that are independent of primary or alternate key columns |
| View | 
|
Data structure that results from a SQL query and that is built from data in one or more tables |
| Procedure | 
|
Precompiled collection of SQL statements stored under a name in the database and processed as a unit |
| Web service | — | Collection of SQL statements stored in a database to retrieve relational data in HTML, XML, WSDL or plain text format, through HTTP or SOAP requests |
| Web operation | — | Sub-object of a Web service containing a SQL statement and displaying Web parameters and result columns |
| Object | Tool | Description |
|---|---|---|
| Cube | 
|
Collection of measures related to aspects of the business and used to carry out a decision support investigation |
| Fact | — | Group of measures used among cubes |
| Dimension | 
|
Axis of investigation of a cube (time, product, geography) |
| Association | 
|
Association that relates a cube to a dimension |
| Attribute | — | Used to qualify a dimension. For example, attribute Year qualifies the Date dimension |
| Fact Measure | — | Variable linked to a fact, used as the focus of a decision support investigation |
| Hierarchy | — | Organizational structure that describes a traversal pattern though a dimension |
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