Entity is an object-relational mapping tool for the D programming language. Referring to the design idea of JPA. support PostgreSQL / MySQL / SQLite.

## Support databases

    PostgreSQL 9.0+
    MySQL 5.1+
    SQLite 3.7.11+

## Depends

    database

## Simple code

import entity;

@Table("user")
class User : Entity
{
    @PrimaryKey
    @AutoIncrement
    int id;

    string name;
    double money;
    string email;
    bool status;
}

void main()
{
    DatabaseOption options = new DatabaseOption("mysql://root:123456@localhost:3306/huntblog?charset=utf-8");
    EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("default", options);
    EntityManager em = entityManagerFactory.createEntityManager();

    // begin transaction
    em.getTransaction().begin();

    // define your database existing row id in here
    int id = 10;

    auto user = em.find!User(id);
    log("User name is: ", user.name);

    // commit transaction
    em.getTransaction().commit();

    em.close();
    entityManagerFactory.close();
}

## Insert row

    auto user = new User();
    user.name = "Brian";
    user.email = "brian@huntlabs.cn";
    user.money = 99.9;

    // insert user
    em.persist(user);
    log("User id is: ", user.id);

## Delete row

    int n = em.remove!User(id);
    log("The member of users deleted is: ", n);

## Update row

    auto user = em.find!User(id);
    log("User name is: ", user.name);
    user.name = "zoujiaqing";
    em.merge!User(user);
    log("The number of users updated is: ", n);

## Use CriteriaQuery to find

    // create CriteriaBuilder object from em
    CriteriaBuilder builder = em.getCriteriaBuilder();

    CriteriaQuery!User criteriaQuery = builder.createQuery!User;
    Root!User root = criteriaQuery.from();
    Predicate p1 = builder.equal(root.User.id, id);
    TypedQuery!User typedQuery = em.createQuery(criteriaQuery.select(root).where(p1));

    auto user =  cast(User)(typedQuery.getSingleResult());

    log("User name is: ", user.name);

## Use CriteriaQuery to Multi-condition find

    // create CriteriaBuilder object from em
    CriteriaBuilder builder = em.getCriteriaBuilder();

    CriteriaQuery!User criteriaQuery = builder.createQuery!User;
    Root!User root = criteriaQuery.from();

    Predicate p1 = builder.lt(root.User.id, 1000);  // User id is less than 1000.
    Predicate p2 = builder.gt(root.User.money, 0);  // User money is greater than 0.
    Predicate p3 = builder.like(root.User.name, "z%");  // User name prefix is z.

    TypedQuery!User typedQuery = em.createQuery(criteriaQuery.select(root).where(builder.and(p1, p2), p3));
    User[] users typedQuery.getResultList();

    log("The number of users found is: ", users.length);

## Links

http://code.dlang.org/packages/entity
https://github.com/huntlabs/entity