Database Class Relationships

A common application-level database operation is implementing a relationship between database classes. For developers familiar with relational databases and SQL, a join between two tables is implemented by a foreign key in one table referencing a primary key in another table. For example, a simple join on the one-to-many relationship between two tables Department and Employee could be implemented as follows:

 
    select e.name, d.name from Employee e 
    inner join Department d d.dept_no = d.dept_no;
     

Here the key field (column) dept_no would be a primary key in Department and a foreign key in Employee.

In eXtremeDB, relationships and joins between tables can be implemented in a number of ways, each having distinct advantages and costs in terms of memory overhead and performance.

The APIs for creating relationships between classes (tables) are specific to the programming language used. Please use the links below to view detailed explanations and examples for your development environment:

C	Database class relationships in C
C++	Database class relationships in C++
Java	Database class relationships in Java
Python	Database class relationships in Python
C#	Database class relationships in C#