Rails简单练习
对Rails的一个简单的练习
一个学生和教师的CRUD，以及简单的ajax应用。学生和教师为多对一得关系
model为：
class Student < ActiveRecord::Base belongs_to :teacher end class Teacher < ActiveRecord::Base has_many :students,:dependent=>:delete_all end
migrate为：
class CreateTeachers < ActiveRecord::Migration
def self.up
create_table :teachers,:force=>true do |t|
t.column :name,:string
end
end
def self.down
drop_table :teachers
end
end
class CreateStudents < ActiveRecord::Migration
def self.up
create_table :students,:force=>true do |t|
t.column :name,:string
t.column :teacher_id,:integer
add_index :students,:teacher_id
end
end
def self.down
drop_table :students
end
end
执行rake db:migrate 后，可以看到没有在数据库中使用外键，只是在teachar_id上面增加了索引
控制器代码： 功能为列出所有的学生和教师，增加和删除学生与教师
#coding:utf-8
class HomeController < ApplicationController
#默认页面
def index
list
render :action => "index"
end
# 如果提交的姓名不为空，则增加学生，然后跳转到index
def new
# 如果姓名不为空则执行保存操作
if check_n
entity = Student.new
unless params[:teacher_id].nil?
unless params[:teacher_id]=="0"
entity.teacher = Teacher.find params[:teacher_id]
end
end
if check_type == "teacher"
entity = Teacher.new
end
entity.name = @name
entity.save
flash[:error] = "OK"
end
redirect_to :action => "index"
end
# 删除学生/老师
def delete
begin
# 根据类型进行判断，执行对应代码
logger.debug "debug================================="
logger.debug "the type and id is type:#{params[:type]},id:#{params[:id]}"
if params[:type] and params[:type]=="student"
Student.destroy(params[:id])
else
t = Teacher.find params[:id]
# 取得级联删除的学生的id
id_array = t.student_ids.to_s
t.destroy
logger.debug "debug================================="
logger.debug "the array is #{id_array.to_s}"
end
rescue =>e
logger.debug(e)
#如果删除失败则不返回任何信息
# render :text => e.to_s
return
end
# 如果是删除老师则返回一个包含有级联删除的学生id的数组字符串
if id_array.nil?
render :text => "OK"
else
render :text => id_array
end
end
private
# 列出所有的学生和老师
def list
@students = Student.find :all
@teachers = Teacher.find :all
@teacher_name = []
for st in @students
th = st.teacher
unless th.nil?
@teacher_name << st.teacher.name
else
@teacher_name << "none"
end
# logger.debug "debug================================="
# logger.debug "the student's teacher is #{st.teacher}"
end
end
# 检测提交的姓名是否为空
def check_n
@name = params[:name]
logger.debug "debug================================="
logger.debug "this name is #{@name}"
if @name.nil? or @name.strip.empty?
flash[:error] = "name should not be empty."
return false
else
return true
end
end
#判断要保存的是学生还老师
def check_type
type = params[:type]
logger.debug "debug================================="
logger.debug "the type is #{type}"
if type.nil?
raise "未知的类型。"
elsif type == "student"
return type
elsif type == "teacher"
return type
else
raise "未知的类型"
end
end
end
index.rhtml如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<base href="/"/>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<title>test</title>
<script type="text/javascript" src="javascripts/prototype.js"></script>
<script type="text/javascript">
function addEvent(){
//为每个a标签注册单击事件
$$("a").each(function(a){
a.observe("click",deleteEntity)
})
}
//给教师列表注册时间晕
function teacherList(){
select = document.getElementById("type")
value = select.options[select.selectedIndex].text
if (value=="学生")
$('teacher_id').show()
else{
$("teacher_id").hide()
}
}
// 取得数据的id和类型然后调用Ajax请求
function deleteEntity(e){
a = Event.element(e)
//取得a标签的id内容,此为要删除的数据在数据库中的主键id
id = a.identify()
type = "student"
if(a.hasClassName("teacher")){
type="teacher"
}
//向后台发送删除请求晕
ajax(a,id,type)
}
function ajax(a,id,type){
// alert(id)
new Ajax.Request("home/delete",{parameters:{id:id,type:type},onSuccess:callback})
function callback(data){
//取得服务器返回的处理结果
var result = data.responseText
removeLi(a)
//如果返回的不是OK,则刷新学生列表晕
if (result!="OK")
refreshList(result)
}
}
function refreshList(array){
ids = eval(array)
if(ids.length==0) return
$$("ul")[0].childElements().each(function(li){
li.childElements().each(function(a){
id = a.identify()
for(i=0;i<ids.length;i++){
if (id == ids[i])
removeLi(a)
}
})
})
}
function removeLi(a){
a.ancestors()[0].remove()
}
// 添加事件
Event.observe(window,"load",addEvent)
</script>
</head>
<body>
<p>所有学生：</p>
<ul>
<% @students.each_index do |index| %>
<li>
学生姓名:<%=@students[index].name%>
所属的教师:<%=@teacher_name[index]%>
<a href="javascript:void(0);" class="student" id="<%=@students[index].id%>">删除</a>
</li>
<%end%>
</ul>
<p>所有教师：</p>
<ul>
<% @teachers.each do |teacher| %>
<li>
教师姓名:<%=teacher.name%>
<a href="javascript:void(0);" class="teacher" id="<%=teacher.id%>">删除</a>
</li>
<%end%>
</ul>
<p />
<hr />
<p>增加学生/教师<br /></p>
<% form_tag("home/new") do-%>
姓名:<input name="name"/>
<p />
类别:
<select onchange="teacherList()" name="type" id="type">
<option value="student">学生</option>
<option value="teacher">教师</option>
</select>
<div id="teacher_id">
所属的教师:
<select name="teacher_id">
<option value="0">暂无</option>
<% @teachers.each do |teacher| %>
<option value="<%=teacher.id%>"><%=teacher.name%></option>
<%end%>
</select>
</div>
<p />
<input type="submit" value="确定"/>
<%end-%>
<p>处理结果:<span style="color: red"><%=flash[:error]%></span></p>
</body>
</html>
上面的
//给教师列表注册时间晕
//向后台发送删除请求晕
最后的'晕'如果不加上，就会出现这个错误 invalid byte sequence in GBK。很诡异啊，可能是bug吧。看了下rubyAPI文档，发现添加Encoding.default_internal="UTF-8"和Encoding.default_external="UTF-8"到application_controller.rb中就可以解决这个诡异的问题。
还有个问题：如果表单输入中文，即数据库中存入中文时还是会报 incompatible character encodings: GBK and ASCII-8BIT的错误
ruby为ruby1.9.1版本
rails为rails2.3.8版本