Codeigniter：如何检查用户名是否已经存在从MySQL数据库

Question

我目前正在codeigniter上工作。我不擅长使用框架。我有一个员工的注册表，我希望它显示“用户名已存在”旁边的用户名输入后，我提交了一个按钮。

下面是表从MySQL数据库中的图像：

Image of tables from mysql database

这里是控制器（home.php）：

public function viewAddEmployeeForm() { 
     $this->load->model('Model_home'); 
     $data = array(); 
     $data['dropdown'] = $this->Model_home->get_dropdown(); 
     $this->load->view('imports/header'); 
     $this->load->view('imports/menu'); 
     $this->load->view('emp_add', $data); 
    } 

public function saveEmployee() { 
     $this->load->model('Model_home'); 
     $p = new Model_home(); 
     $p->date_employed = $this->input->post('date_emp'); 
     $p->designation_id = $this->input->post('emp_desi'); 
     $p->username = $this->input->post('username'); 
     $p->password = $this->input->post('pswrd'); 
     $p->name = $this->input->post('emp_name'); 
     $p->midname = $this->input->post('emp_mname'); 
     $p->lastname = $this->input->post('emp_lname'); 
     $p->CityAddress = $this->input->post('emp_cadd'); 
     $p->license_num = $this->input->post('emp_license'); 
     $p->TIN_num = $this->input->post('emp_tin'); 
     $p->SSSNo = $this->input->post('emp_sss'); 
     $p->PhilHealth = $this->input->post('emp_ph'); 
     $p->DoB = $this->input->post('emp_dob'); 
     $p->Gender = $this->input->post('emp_gender'); 
     $p->contnum = $this->input->post('emp_mobno'); 
     $p->ContactPerson = $this->input->post('emp_contpers'); 
     $p->ContactPerson_Num = $this->input->post('emp_contpersnum'); 
     $p->ContactPerson_Add = $this->input->post('emp_contpersadd'); 

     if($p->designation_id == 1){ 
      $p->user_type = 0; 
     }else{ 
      $p->user_type = 1; 
     } 
     $result = $p->saveEmployee(); 
     if (!$result) { 
      echo mysqli_error($result); 
     } 
     else { 
      redirect('home/goSettings', 'refresh'); 
     } 
    } 

这里是视图：（emp_add.php） ：

<h1>Add Employee</h1> 
<br> 
<?php echo form_open('home/saveEmployee',array('class'=>'form-horizontal'));?> 

<h4> Personal Information </h4> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12" for="first-name">First Name <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_name" name="emp_name" required="required" class="form-control col-md-7 col-xs-12"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12" for="last-name">Last Name <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_lname" name="emp_lname" required="required" class="form-control col-md-7 col-xs-12"> 
    </div> 
</div> 
<div class="form-group"> 
    <label for="middle-name" class="control-label col-md-3 col-sm-3 col-xs-12">Middle Name/Initial</label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input id="emp_mname" name="emp_mname" class="optional form-control col-md-7 col-xs-12" type="text"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Gender</label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <div id="gender" class="btn-group" data-toggle="buttons"> 
      <select id="emp_gender" name="emp_gender" class="form-control"> 
       <option id="emp_gender" name="emp_gender" value="Male">Male</option> 
       <option id="emp_gender" name="emp_gender" value="Female">Female</option> 
      </select> 
     </div> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Date Of Birth <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input id="emp_dob" name="emp_dob" class="date-picker form-control col-md-7 col-xs-12" required="required" type="date"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Address <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input id="emp_cadd" name="emp_cadd" class="form-control col-md-7 col-xs-12" required="required" type="text"> 
    </div> 
</div> 
<h4> Employee Identification </h4> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">License Number</label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_license" name="emp_license" class="optional form-control"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">TIN Number</label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_tin" name="emp_tin" class="optional form-control"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">SSS Number</label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_sss" name="emp_sss" class="optional form-control" > 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">PhilHealth</label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_ph" name="emp_ph" class="optional form-control" > 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Username <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="username" name="username" required="required" class="form-control col-md-7 col-xs-12" onblur="return check_username();"> 
     <div id="Info"></div> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Password <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="password" id="pswrd" name="pswrd" required="required" class="form-control col-md-7 col-xs-12"> 
    </div> 
</div> 
<h4> Work details </h4> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Date Employed <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input id="date_emp" name="date_emp" class="date-picker form-control col-md-7 col-xs-12" required="required" type="date"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Designation <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 

     <?php echo form_dropdown('emp_desi', $dropdown, '', 'class="form-control" id="emp_desi"'); ?> 

    </div> 
</div> 
<h4> Contact Information </h4> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Mobile Number <span class="required">*</span></label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_mobno" name="emp_mobno" class="form-control" required="required" > 
    </div> 
</div> 
<h4> Contact Person </h4> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Name <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_contpers" name="emp_contpers" required="required" class="form-control col-md-7 col-xs-12"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Address <span class="required">*</span> 
    </label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_contpersadd" name="emp_contpersadd" required="required" class="form-control col-md-7 col-xs-12"> 
    </div> 
</div> 
<div class="form-group"> 
    <label class="control-label col-md-3 col-sm-3 col-xs-12">Mobile Number <span class="required">*</span></label> 
    <div class="col-md-6 col-sm-6 col-xs-12"> 
     <input type="text" id="emp_contpersnum" name="emp_contpersnum" required="required" class="form-control" > 
    </div> 
</div>         
<div class="ln_solid"></div> 
<div class="form-group"> 
    <div class="col-md-6 col-sm-6 col-xs-12 col-md-offset-3"> 
     <button type="submit" class="btn btn-success" name="emp_submit" id="emp_submit" onclick="alert('You have successfully added an employee')">Submit</button> 
    </div> 
</div> 

</form> 

这里是模型（model_home.php）：

public function saveEmployee() { 
     if (isset($this->empnum)) { 
      $query = $this->updateEmployee(); 
     } 
     else { 
      $query = $this->addEmployee(); 
     } 

     return $query; 
    } 

public function get_dropdown() { 
    $result = $this->db->select('designation_id, designation')->get('designation')->result_array(); 
    $dropdown = array(); 
    foreach($result as $r) { 
     $dropdown[$r['designation_id']] = $r['designation']; 
    } 
    return $dropdown; 
} 

Answer 1

试试这个

$this->form_validation->set_rules('username', 'Username', 'required|is_unique[users.username]'); 

这里is_unique[users.username]，users指用户表& username指字段名的用户表。这将自动检查用户表中的用户名。

Answer 2

要查看数据库中是否存在某些内容，通常要么使用LIKE命令，要么使用REGEXP命令来测试该条目是否已经存在。请参阅本文如何使用REGEXP：

mySQL regex in the where clause

如果该项目已经存在，将返回该项目。如果不是，它应该返回NULL或什么都不返回

然后你要做的就是刷新预先存在的HTML网页。您在当前网页中唯一需要修改的部分PHP代码只是回应了返回的信息。所以简单的事情如下：

<?php echo $foundIt; ?> 

你把那个放在他们放在用户名（或用户名显示）旁边。如果没有发现任何内容，请务必使用空白字段声明该变量。 I.E .:

$foundIt = ""; 

否则你的网页会产生一个错误，说它是未定义的。

我看到sriAnkush回答了你的问题。我的答案是使用纯HTML。看起来他正在使用CodeIgniter。 :-)

Answer 3

尝试像这样的控制器功能。在$username获取用户名并将其传递给模型。使用选择查询，其中用户名等于$username并返回数组。如果有任何类似的用户名$result将大于或等于1.所以它会显示用户名已经存在，否则它会保存你的数据。

public function saveEmployee() { 
    $username=$this->input->post('username'); 
    $result=$this->model->checkUsername($username); 

    if($result>=1){ 
     echo "Username Already exists"; 
    } 
    else{ 
     // Query to save the username and data;   
    } 
} 

祝你好运！