How to Use the Generate ORM Code?
The following sections demonstrate how to use the generate ORM code with factory method persistent API.
Inserting records
- Create persistent object with factory create method.
- Save persistent object with save method.
The following codes demonstrate how to insert a Product record:
PersistentTransaction t = ErdPersistentManager.instance().getSession().beginTransaction();
try {
Product product = ProductFactory.createProduct();
product.setName("ABC Keyboard");
product.setPrice(24.5);
product.save();
}
catch (Exception e) {
t.rollback();
}
Selecting records
Factory method provides a convinient listByQuery method, accept condition and order by as parameter` and return array of persistent object.
The following codes demonstrate how to select a list of Product records, null for condition parameter will select all records, null for order by parameter does not sort in any order:
Product[] products = ProductFactory.listProductByQuery(null, null);
for (int i = 0; i < products.length; i++) {
System.out.println(products[i]);
}
Another useful method to select a persistent object by ID is loadByORMID. The following codes demonstrate how to select a lProuct record by ID.
Product product = ProductFactory.loadProductByORMID(1);
Updating records
- Select a persistent object from database.
- Update the persistent object.
- Save persistent object with save method.
The following codes demonstrate how to update a Product record:
PersistentTransaction t = ErdPersistentManager.instance().getSession().beginTransaction();
try {
Product product = ProductFactory.loadProductByORMID(1);
product.setName("DEF Keyboard");
product.save();
}
catch (Exception e) {
t.rollback();
}
Deleting records
- Select a persistent object from database.
- Delete persistent object with delete method.
The following codes demonstrate how to delete a Product record:
PersistentTransaction t = ErdPersistentManager.instance().getSession().beginTransaction();
try {
Product product = ProductFactory.loadProductByORMID(1);
product.delete();
}
catch (Exception e) {
t.rollback();
}
Related Resources
The following resources may help you to learn more about the topic discussed in this page.
| 3. Persistent API | Table of Contents | 5. Customizing getter and setter body |
