Oracle collections are database types that allow you to store sets of elements, similar to arrays and collections in Java. Storing data in collections is closer to the object oriented paradigm. The data stored in an embedded collection may be accessed faster by the database than if stored in two separate tables. Oracle database has 3 types of collections, which are varrays, nested tables and associative arrays. A varray is an ordered set of elements with index, similar to an array in Java.

Annotations and Java configurations are more common in newer Spring projects. However, there are many old projects that continue to use XML configuration. Through the autowiring feature, spring will intelligently guess some of the bean injection without needing to configure explicitly. Spring can do autowiring based on the type of the bean, name of the bean, and constructor of the bean. Default is autowire by type.

We saw how to inject primitive types and String properties through setter injection and constructor injection. We will see how to inject other objects. A class might have references to other classes and when an object of the outer class is created, Spring can inject objects for the referenced inner objects as well based on bean definitions. We will follow the xml style configuration here, but this can also be done without using XML.

The ApplicationContext is the central interface within a Spring application for providing configuration information to the application. It is read-only at run time, but can be reloaded if necessary and supported by the application. A number of classes implement the ApplicationContext interface, allowing for a variety of configuration options and types of applications.

The ApplicationContext provides:

• Bean factory methods for accessing application components.

Procedures and functions encapsulate a group of SQL and PL/SQL statements. A function is different from stored procedure in that a function must return a value.

Creating procedures and functions

You can create a procedure using the CREATE PROCEDURE statement as:

CREATE PROCEDURE insert_emp_details_p(

emp_id_var IN emp.emp_id%TYPE,

emp_name_var IN emp.emp_name%TYPE