PHP框架CI常用整理

一、数据库参考

（一）查询

1. 常规查询

   $query = $this->db->query(‘YOUR QUERY HERE’);

2. 查询绑定

   $sql = “SELECT * FROM some_table WHERE id IN ? AND status = ? AND author = ?”;
   $this->db->query($sql, array(array(3, 6), ‘live’, ‘Rick’));

（二）查询结果

1. 对象结果

   $query->result()

2. 数组结果

   $query->result_array()

3. 结果行

   $row = $query->row();

4. 结果行数组

   $row = $query->row_array();

（三）查询辅助函数

1. 返回查询结果数

   $query->num_rows();

2. 该方法返回上一次执行的查询语句（是查询语句，不是结果）

   $this->db->last_query()

3. 该方法用于获取数据表的总行数，第一个参数为表名

   echo $this->db->count_all(‘my_table’);

（四）查询构造器

4.1 查询

1. $this->db->get()

   $query = $this->db->get(‘mytable’, 10, 20);
   
   Executes: SELECT * FROM mytable LIMIT 20, 10``

2. $this->db->select()

   $this->db->select(‘title, content, date’);
   
   $query = $this->db->get(‘mytable’);

3. $this->db->select_max()
4. $this->db->select_min()
5. $this->db->select_avg()
6. $this->db->select_sum()
7. $this->db->from()
8. $this->db->join()

   $this->db->join(‘comments’, ‘comments.id = blogs.id’, ‘left’);

4.2 搜索

1. $this->db->where()

   1. 简单的 key/value 方式:
      $this->db->where(‘name’, $name);
   2. 自定义 key/value 方式:
      $this->db->where(‘id <’, $id);
   3. 关联数组方式:
      $array = array(‘name !=’ => $name, ‘id <’ => $id, ‘date >’ => $date);
      
      $this->db->where($array);

2. $this->db->or_where()
3. $this->db->where_in()
4. $this->db->or_where_in()
5. $this->db->where_not_in()
6. $this->db->or_where_not_in()

4.3 模糊查询

1. $this->db->like()

   简单 key/value 方式:
   
   1. $this->db->like(‘title’, ‘match’, ‘before’); // Produces: WHERE title LIKE ‘%match’ ESCAPE ‘!’
   
   2. $this->db->like(‘title’, ‘match’, ‘after’); // Produces: WHERE title LIKE ‘match%’ ESCAPE ‘!’
   
   3. $this->db->like(‘title’, ‘match’, ‘both’); // Produces: WHERE title LIKE ‘%match%’ ESCAPE ‘!’

2. $this->db->not_like()
3. $this->db->group_by()
4. $this->db->distinct()
5. $this->db->having()

4.4 排序

1. $this->db->order_by()

   $this->db->order_by(‘title’, ‘DESC’);

4.5 分页与计数

1. $this->db->limit() 注意这里参数的顺序，第一个参数是count，第二次才是start

   $this->db->limit(10, 20);

2. $this->db->count_all_results()
3. $this->db->count_all()

4.6 插入数据

1. $this->db->insert()
2. $this->db->insert_batch()

4.7 更新数据

1. $this->db->replace()
2. $this->db->update()
3. $this->db->update_batch()
4. $this->db->delete()

（四）事务

1. 运行事务

$this->db->trans_start();

$this->db->query(‘AN SQL QUERY…’);

$this->db->query(‘ANOTHER QUERY…’);

$this->db->trans_complete(); <br> if ($this->db->trans_status() === FALSE)

{

// generate an error… or use the > log_message() function to log your error

}