ActiveJDBC：save（）只能为自动生成的主键生成插入吗？

Question

I recently started using ActiveJDBC. I have the following table (postgresql)

CREATE TABLE users (
    id                   uuid PRIMARY KEY,
    email                text UNIQUE NOT NULL,
    password             text,
    <some more nullable columns>
    created_at           timestamp with time zone NOT NULL default (now() at time zone 'utc'),
    updated_at           timestamp with time zone
);

As you can see, the primary key is of type uuid and has no auto-generate value of any kind.

This is my User class which models the table :

public class User extends Model
{
    public User() {
        setId(UUID.randomUUID());  // sets value to primary key
    }
...
}

This is my attempt to create a new row and insert it :

    User u = new User();
    System.out.println(u.saveIt());

actually, I expected the insert to fail, since I did not set any value for mandatory email column. However, simply got false as return value. when I turned on logging, I saw that the framework generated an update sql instead of insert:

[main] INFO org.javalite.activejdbc.DB - Query: "UPDATE users SET email = ?, ..., updated_at = ? WHERE id = ?", with parameters: <null>, <null>, <null>, <null>, <null>, <null>, <null>, <2016-01-07 17:30:46.025>, <0621fbdb-5b95-4ee7-a474-8ee9165e2982>, took: 1 milliseconds

so I looked at the save() method inside org.javalite.activejdbc.Model class and saw this piece of code:

    if (getId() == null) {
        result = insert();
    } else {
        result = update();
    }

does this mean that id column has to be empty in order for an insert to be generated ? if this is true this is unacceptable, so I must be missing something.

Answer 1

@sharonbn, please, see this documentation page: http://javalite.io/surrogate_primary_keys . ActiveJDBC depends on autogenerated IDs. If the ID == null, the frameworks assumes this is a new record, and generates INSERT statement. If it is non-null, it is assumed the record already exists, and generates UPDATE.

In your case, you will need to explicitly call user.insert() instead of user.saveIt() . This is an 'expert' mode in cases when developers want to be in control of ID management. Further, the method user.update() is private. So for you to insert a new record, you will be calling

user.insert();

and for updates:

user.save(); // or: user.saveIt();

, depending on what you want.