A domain class fulfills the M in the Model View Controller (MVC) pattern and represents a persistent entity that is mapped onto an underlying database table. This class will map automatically to a table in the database called book (the same name as the class). This behaviour is customizable through the ORM Domain. GORM is Grails’ object relational mapping (ORM) implementation, which sits on top of the very popular Hibernate framework. If you are familiar.
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Nov 29, Beginner comments. For example, here is a code snippet on how we save a record in the database using plain JDBC: Wouldn’t it be cool if we could save information to the database by having this instead?
ORM frameworks objective girm to present an API where you can just think and program in objects, and the underlying framework will handle how to interface with the relational database. Create a groovy class inside the domain folder E. Read In case you know the primary key id of a specific row e. Update Updating an existing is as simple as calling the save method of the domain instance. For example, to increase the salary of a person: Delete To delete, just invoke the delete method on the domain instance: Number of gom in person table: If you like my posts, like my Facebook page please: Using it just makes implementation of business logic a breeze.
Working with a database becomes so easy.
7 Object Relational Mapping (GORM)
Don’t worry otherwise as GORM is straightforward and easy to learn. Object-relational mapping ORM Relational database is still the most popular way to store and retrieve information because the technology is very mature and it has many software options. Because you think in terms of tables in database, while you think in terms of Classes and objects in Java. Wouldn’t it be easier and more efficient if we just think in terms of objects and forget about tables?
The Grails Framework
Configuration Since Grails is a framework that don’t want to get in the way, it has a default database configuration already so that you could start coding your business logic right away. By default, it gom an embedded H2 database.
But if you wish to modify this, the config file to edit is DataSource. Domain Object Create a groovy class inside the domain folder E.
GORM 6 – A powerful Groovy-based data access toolkit for the JVM
You don’t have to create the tables manually in your database or write an sql statement for this. The correct sql data type will be applied E.
The generated table in MySQL is below: Notice that Grails automatically add 2 columns id and version. Column id will be the primary key for the table. Column version is used to version the updates to the row. This is usually graild for optimistic locking. Create, Read, Update, Delete CRUD When you have prepared your domain class, you can then immediately write code to create, read, update, or delete records to the database already without writing any plumbing code.
Create Record To insert a row to the person table, your code will look like this: But in GORM, it seems they are merged together. Some are dynamically available.
Just to give a quick overview, you can do these thigs: Another advantage not mentioned above is that Grails applications are database agnostic. Since GORM provides an abstraction layer from the database i.