Data Model Oracle DBMS

Table of Contents

• Table Relationships
  • Examples demonstrating the various types of relationships between LeasePak database tables
• Data Model Diagrams
  • Diagrams for a range of common and representative LeasePak table relationships

Introduction

The LeasePak Data Model is a collection of data model diagrams. The data model diagrams depict the relationships among the core LeasePak tables. The Data Model, along with the table and index definitions in the Database Reference manual, can be used as documentation when joining tables together for custom reporting and ad hoc queries.

A data model diagram consists of a set of tables and the relationships between the tables. The tables are either actual tables or "virtual tables"— that is, "views". If a table name begins with a "v", it is a view.

A table is represented by a rectangular box, referred to as a "table box". The name and description of the table are displayed at the top of the table box. A relationship between two tables is represented by a line connecting two table boxes. The line is referred to as the "relationship line".

The "join columns" are the columns used to join tables together with SQL. In a data model diagram, the names of the join columns are displayed on the relationship line, and also within the table boxes. When the names of the join columns are the same in both tables, the join column name is displayed once on the relationship line. When they are different, both join column names are displayed on the relationship line.

  The join columns are usually but not always indexed. Performing a join using non-indexed columns requires a table scan, which is much slower than indexed access. Refer to the index definitions in LeasePak Database Objects for a complete list of the indexed columns in LeasePak tables.

Each table box contains the names and descriptions of relevant columns from the table: the join columns and sometimes additional key and data columns. Refer to the table definitions in LeasePak Database Objects for a complete list of the columns in LeasePak tables.