EntityD 語言的 ORM 框架

Entity 是 D 語言( DLang )數(shù)據(jù)庫操作 ORM 框架，設(shè)計(jì)參照 javax JPA 實(shí)現(xiàn)，具有很好的擴(kuò)展性和規(guī)范性，數(shù)據(jù)庫驅(qū)動依賴 HuntLabs 開發(fā)的 database for dlang 。

特性

1. 實(shí)現(xiàn)了完整的 CriteriaQuery 支持

2. 對 Repository 也有部分封裝

3. 完全對象化查詢，不用考慮底層數(shù)據(jù)庫驅(qū)動

4. 實(shí)現(xiàn) EQL（Entity Query Language）實(shí)現(xiàn)對象化 SQL 查詢語言

支持的數(shù)據(jù)庫

• PostgreSQL 9.0+

• MySQL 5.1+

使用示例

import hunt.entity;

@Table("users")
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 = "[email protected]";
    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 number 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 = 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);

EQL 使用

// Example for sample SELECT
auto query = em.createQuery!(User)("SELECT u FROM User u");

foreach(user; query.getResultList())
{
	logDebug(user.name);
}