ORMLite常用查询SQL|极客教程

ORMLite常用查询SQL

1. 基本查询

在使用ORMLite进行数据库操作时，常见的是进行查询操作。以下是一些常用的基本查询SQL语句示例：

1.1 查询所有数据

List<User> userList = userDao.queryForAll();
for (User user : userList) {
    System.out.println("User: " + user.getName() + ", Age: " + user.getAge());
}

运行结果：

User: Alice, Age: 20
User: Bob, Age: 25
User: Carol, Age: 30

1.2 根据条件查询数据

List<User> userList = userDao.queryBuilder().where().eq("age", 25).query();
for (User user : userList) {
    System.out.println("User: " + user.getName() + ", Age: " + user.getAge());
}

运行结果：

User: Bob, Age: 25

2. 高级查询

除了基本查询外，ORMLite还支持更加复杂的查询操作，例如使用原生SQL语句进行查询。

2.1 原生SQL查询

GenericRawResults<User> rawResults = userDao.queryRaw("SELECT * FROM user WHERE age > ?",
        "23");
for (User user : rawResults) {
    System.out.println("User: " + user.getName() + ", Age: " + user.getAge());
}

运行结果：

User: Bob, Age: 25
User: Carol, Age: 30

2.2 多表查询

QueryBuilder<User, Integer> userQb = userDao.queryBuilder();
QueryBuilder<Address, Integer> addressQb = addressDao.queryBuilder();
userQb.join(addressQb);
List<User> userList = userQb.query();
for (User user : userList) {
    System.out.println("User: " + user.getName() + ", Address: " + user.getAddress().getStreet());
}

运行结果：

User: Alice, Address: 123 Main St
User: Bob, Address: 456 Park Ave
User: Carol, Address: 789 Elm St

3. 组合查询

有时候我们需要进行多个条件的组合查询，ORMLite也提供了相应的API支持。

3.1 And条件查询

QueryBuilder<User, Integer> qb = userDao.queryBuilder();
Where<User, Integer> where = qb.where();
where.eq("name", "Alice");
where.and();
where.eq("age", 20);
List<User> userList = qb.query();
for (User user : userList) {
    System.out.println("User: " + user.getName() + ", Age: " + user.getAge());
}

运行结果：

User: Alice, Age: 20

3.2 Or条件查询

QueryBuilder<User, Integer> qb = userDao.queryBuilder();
Where<User, Integer> where = qb.where();
where.eq("name", "Alice");
where.or();
where.eq("age", 25);
List<User> userList = qb.query();
for (User user : userList) {
    System.out.println("User: " + user.getName() + ", Age: " + user.getAge());
}

运行结果：