CI框架的数据操作（增删改查）方法总结

<?php
class demo_model extends CI_Model {
public function __construct()
{
$this->load->database();
}
//- 查询实例
public function select()
{
//SELECT * FROM mytable
$query = $this->db->get('mytable');

//SELECT * FROM mytable LIMIT 20, 10
//说明:第二参数是每页纪录数，第三个参数是偏移
$query = $this->db->get('mytable', 10, 20);

//SELECT * FROM mytable where id=$id LIMIT  $offset,$limit
$query = $this->db->get_where('mytable',array('id' => $id),$limit,$offset);

//SELECT title, content, date FROM mytable
$this->db->select('title, content, date');
$query = $this->db->get('mytable');

//SELECT MAX(age) as age FROM members
$this->db->select_max('age');
$query = $this->db->get('members');

//SELECT MIN(age) as age FROM members
$this->db->select_min('age');
$query = $this->db->get('members');

//SELECT MAX(age) as member_age FROM members
$this->db->select_max('age', 'member_age');
$query = $this->db->get('members');

//SELECT SUM(age) as member_age FROM members
$this->db->select_sum('age','member_age');
$query = $this->db->get('members');

//SELECT title, content, date FROM mytable
$this->db->select('title, content, date');
$this->db->from('mytable');
$query = $this->db->get();

//SELECT * FROM blogs
//JOIN comments ON comments.id = blogs.id
$this->db->select('*');
$this->db->from('blogs');
$this->db->join('comments', 'comments.id = blogs.id');
$query = $this->db->get();

//可选参数:left,right, outer, inner, left outer,right outer.
//LEFT JOIN comments ON comments.id = blogs.id
$this->db->join('comments', 'comments.id = blogs.id', 'left');

//WHERE name = 'joe'
$this->db->where('name','joe');

//WHERE name = 'joe' and id=1
$this->db->where('name','joe');
$this->db->where('id',1);

//WHERE name != 'joe' and id < 45
$this->db->where('name !=', 'joe');
$this->db->where('id <', 45);

//WHERE name = 'Joe' AND title = 'boss'
$array = array('name' => $name, 'title' => $title);
$this->db->where($array);

//WHERE name != 'Joe' AND id<1
$array = array('name!=' => $name, 'id<' => $id);
$this->db->where($array);

//可以自定义where
$where = "name='Joe' AND status='boss' OR status='active'";
$this->db->where($where);

//WHERE name != 'Joe' OR id > 50
$this->db->where('name !=', $name);
$this->db->or_where('id >', $id);

//WHERE username IN ('Frank', 'Todd', 'James')
$names = array('Frank', 'Todd', 'James');
$this->db->where_in('username', $names);

//OR username IN ('Frank', 'Todd', 'James')
$names = array('Frank', 'Todd', 'James');//in后面只能是数组形式
$this->db->or_where_in('username', $names);

//WHERE username NOT IN ('Frank', 'Todd', 'James')
$names = array('Frank', 'Todd', 'James');
$this->db->where_not_in('username', $names);

//OR username NOT IN ('Frank', 'Todd', 'James')
$names = array('Frank', 'Todd', 'James');
$this->db->or_where_not_in('username', $names);

//WHERE title LIKE '%match%' AND body LIKE '%match%'
$this->db->like('title', 'match');
$this->db->like('body', 'match');

//可选参数:before,after,both,none
//WHERE title LIKE '%match'
$this->db->like('title', 'match', 'before');

// WHERE title LIKE '%match%' AND page1 LIKE '%match%' AND page2 LIKE '%match%'
$array = array('title' => $match, 'page1' => $match, 'page2' => $match);
$this->db->like($array);

// WHERE title LIKE '%match%' OR body LIKE '%match%'
$this->db->like('title', 'match');
$this->db->or_like('body', $match);

// WHERE title NOT LIKE '%match%
$this->db->not_like('title', 'match');

// WHERE title LIKE '%match%' OR body NOT LIKE '%match%'
$this->db->like('title', 'match');
$this->db->or_not_like('body', 'match');

//GROUP BY title
$this->db->group_by("title");

//GROUP BY title, date
$this->db->group_by(array("title", "date"));

//ORDER BY title DESC
$this->db->order_by("title", "desc");

//ORDER BY title DESC, name ASC
$this->db->order_by('title desc, name asc');

//ORDER BY title DESC, name ASC
$this->db->order_by("title", "desc");
$this->db->order_by("name", "asc");

//LIMIT 10
$this->db->limit(10);

//LIMIT 20, 10 (仅限MySQL中。其它数据库有稍微不同的语法)
$this->db->limit(10, 20);

//$this->db->count_all_results('my_table');
}
//插入实例
public function insert()
{
//INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date')
$data = array('title' => 'My title' ,'name' => 'My Name' ,'date' => 'My date');
$this->db->insert('mytable', $data);

//INSERT INTO mytable (title, name, date) VALUES ('My title', 'My name', 'My date'),
//('Another title', 'Another name', 'Another date')
$data = array(
array(
'title' => 'My title' ,
'name' => 'My Name' ,
'date' => 'My date'
),
array(
'title' => 'Another title' ,
'name' => 'Another Name' ,
'date' => 'Another date'
)
);
$this->db->insert_batch('mytable', $data);

//INSERT INTO mytable (field) VALUES (field+1)
$this->db->set('field', 'field+1', FALSE);
$this->db->insert('mytable');

//INSERT INTO mytable (field) VALUES ('field+1')
//$this->db->set('wealth', 'wealth-'.$wealth, FALSE);
$this->db->set('field', 'field+1');
$this->db->insert('mytable');

//
$array = array('name' => $name, 'title' => $title, 'status' => $status);
$this->db->set($array);
$this->db->insert('mytable');
}
//更新实例
public function update()
{
// UPDATE mytable
// SET title = '{$title}', name = '{$name}', date = '{$date}'
// WHERE id = $id
$data = array( 'title' => $title,'name' => $name,'date' => $date);
$this->db->where('id', $id);
$this->db->update('mytable',$data);

$this->db->update('mytable', $data, "id = 4");
//$where=array('id'=>10);
//累加1
$this->db->where($where)->set('views','views+1',false)->update('news_info');

$where = array('id' => $id);
$this->db->update('mytable', $data, $where);
}
//删除实例
public function delete()
{
//DELETE FROM mytable WHERE id = $id
$this->db->delete('mytable', array('id' => $id));

//DELETE FROM table1 WHERE id = 5
//DELETE FROM table2 WHERE id = 5
//DELETE FROM table3 WHERE id = 5
$tables = array('table1', 'table2', 'table3');
$this->db->where('id', '5');
$this->db->delete($tables);

// DELETE FROM mytable
$this->db->empty_table('mytable');
}
//其他实例
public function other()
{
//链式方法
$this->db->select('title')->from('mytable')->where('id', $id)->limit(10, 20);
$query = $this->db->get();

//Active Record 缓存
$this->db->start_cache();
$this->db->select('field1');
$this->db->stop_cache();

$this->db->get('tablename');

//此处输出:SELECT `field1` FROM (`tablename`)

$this->db->select('field2');
$this->db->get('tablename');

//此处输出:SELECT `field1`, `field2` FROM (`tablename`)

$this->db->flush_cache();

$this->db->select('field2');
$this->db->get('tablename');
//此处输出:SELECT `field2` FROM (`tablename`)
}
//显示结果
public function result()
{
return $query->row_array();//返回第一行数据,返回结果为数组
return $query->result_array();//返回多行数据,返回结果为数组
return $query->row();//返回第一行数据
return $query->result();//返回多行数据

return $query->row_array(4);//加参数,可返回第五行数据,用法同上

return $query->num_rows();//当前请求行数

return $query->num_fields();//当前请求的字段数(列数)

$this->db->affected_rows();//更新插入显示影响结果(insert/update)

//显示结果集
return $this->db->query('sql');

//显示插入id
return $this->db->insert_id();

//显示my_table有多少行数据
return $this->db->count_all('my_table');

//显示系统使用的数据库
return $this->db->platform();

//输出系统正在运行的数据库版本号
return $this->db->version();

//显示最近执行的SQL语句：SELECT * FROM sometable....
return $this->db->last_query();

//生成一个SQL语句
//INSERT INTO table_name (name, email, url) VALUES ('Rick', 'rick@example.com', 'example.com')
$data = array('name' => $name, 'email' => $email, 'url' => $url);
return $this->db->insert_string('table_name', $data);

//同上
$data = array('name' => $name, 'email' => $email, 'url' => $url);
$where = "author_id = 1 AND status = 'active'";
return $this->db->update_string('table_name', $data, $where);

//直接执行一个SQL语句
$sql = "";
$result=$this->db->query($sql)->result_array();
}
}