Database relationships are associations between tables that are created using join statements to retrieve data.
The following table describes the database relationships.
|Type of relationship||Description|
|One-to-one||Both tables can have only one record on each side of the relationship.
Each primary key value relates to none or only one record in the related table.
Most one-to-one relationships are forced by business rules and do not flow naturally from the data. Without such a rule, you can typically combine both tables without breaking any normalization rules.
|One-to-many||The primary key table contains only one record that relates to none, one, or many records in the related table.|
|Many-to-many||Each record in both tables can relate to none or any number of records in the other table. These relationships require a third table, called an associate or linking table, because relational systems cannot directly accommodate the relationship.|
In the Database Configuration application, you can define Structured Query Language (SQL) statements for joins, and create relationships between parent and child objects. You can use a join to link data from multiple objects. The parent is the existing object and the child is the object that you are create.