Hibernate have the many annotation to create the relationships between different entities like @OneToOne, @OneToMany, @ManyToOne etc. These annotation takes mappedBy parameter which is used to create the bidirectional mapping. In the bidirectional mapping, parent can retrieve the child and child can retrieve the parent.
Sometime, we would require to generate the value of a column in a table and we don't ask this value from the user. The user input form may not have the input field for that value. Another reason could be you need to change the input value with some logic and then you want to store it in a database. You may have seen the condition where the first time password to be generated automatically and is saved in database.
Here is the example for using the Hibernate with MariaDb database.
First, we need to create the configuration file that is hibernate.cfg.xml which contains the various configuration values lie database name, database URL, database username, password etc. This file is the one time activity you have to do and after than, just keep adding the beans or entities classes in mapping tag but other part will remain as it is.
hibernate.cfg.xml
You will find many cases where you must take multiple columns to build an identified for the data in a row of table. For example, if you are storing the voter list data in table, then to identify the record of a voter, you could search using his name, father name and date of birth as the search criteria because the chances are very low if two ones will have the same values for these three fields.
In database, sometime we have to treat the multiple fields as single a field. For example, address is the single field but again, it has multiple attributes. You can find many properties having the multiple attributes where you have to save the data for all attributes but you will treat that field as a one field.
To create the relationship from one parent to multiple children, we use @OneToMany mapping in hibernate or JPA. Here is the example of how to use @OneToMany annotation.
Sometime, you have to create the relationships among the various tables or entities when we work in database design. Like, if we consider Book and Author entities, there A book may belongs to one author, but a author can belong to many books.
Here is the hibernate example for this scnario.
Here is the example which explains how the Spring and Hibernate work together in a web application which is developed using the Spring MVC.
First, we need to create the Spring MVC project. For this, we will start from configuring the web.xml file as following:
