我在使用核对表中选中的选项尝试从MYSQL中检索数据时遇到了一些麻烦。
我在MYSQL中有2个表,第1个用于degree_names - 它们作为核对表自动输出,第2个用于与每个不同程度名称相关的课程。这两个表都是关系型的,即它们是连接的,因此“courses”是“degree_names”的子表。
所以我的问题是......我该怎么做才能更改我的代码,以便我在核对清单中检查的选项(2个或更多)连接到我的“degree_names”表,然后获取与这些相关的所有课程来自“课程”表的学位?
这是我到目前为止的代码,它直接从degree_name表
输出所有度数的清单 <?php
$username = "root";
$password = "";
$hostname = "localhost";
$dbname = "major_degrees";
$str='';
// Create connection
$conn = new mysqli($hostname, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
$sql = "SELECT degree FROM degree_names";
$result = $conn->query($sql);
$out = '';
$cnt = 0;
if ($result->num_rows > 0) {
// output data of each row from degree_names database as a checklist
while($row = $result->fetch_assoc()) {
$cnt++;
$out .= '<input id="cb_' .$cnt. '" class="checkChange" type="checkbox" name="check" value="ch" id="checky" />' .$row['degree']. '<br/>';
}
echo $out;
}
?>
</b>
</br>
<input class="btn-checkout" type="submit" value="Submit" id="submitBtn" disabled="disabled"/>
</div>
</div>
</form>
</body>
<script src="https://code.jquery.com/jquery-2.2.4.min.js"></script>
<script>
$('.checkChange').change(function() {
var count = 0;
var len = $("[name='check']:checked").length;
// keep a counter for how many boxes have been checked
$('#checkboxes input:checked').each(function() {
count++;
});
// if 2 boxes are checked off then disable the rest
if (count == 2) {
$('#checkboxes input:not(:checked)').each(function() {
$(this).attr("disabled", true);
});
}
// else keep other options enabled
else {
$('#checkboxes input:not(:checked)').each(function() {
$(this).removeAttr('disabled');
});
}
//if exactly 2 boxes are checked off then enable the submit button, or else keep is disabled
if ($(this).is(":checked") && count == 2) {
$("#submitBtn").removeAttr("disabled");
} else {
$("#submitBtn").attr("disabled", "disabled");
}
});
</script>
</html>
答案 0 :(得分:1)
首先清楚majors
和courses
表之间的关系:
您的majors
表格如下:
degree_id | TotalCredits | degree_name
-----------+--------------+--------------------
1 | 8 | Computer Science
2 | 8.5 | Mathematics
3 | 8 | Music and Culture
和courses
表:
id | course_id | degree_id | course_name | credits | pre-requisite | last-offered | status |
----+-----------+-----------+--------------------------------------+---------+---------------+--------------+--------+
1 | CSCA08 | 1 | Introduction to Computer Science I | 0.5 | CSCA48 | Fall 2015 | |
2 | CSCA48 | 1 | Introduction to Computer Science II | 0.5 | CSCB07 | Winter 2015 | |
3 | MATA23 | 2 | Linear Algebra I | 0.5 | MATB24 | Fall 2015 | |
为什么每个复选框都有一个value
?将这些复选框的值设置为degree_id
表的majors
。首先将您的查询更改为:
$sql = "SELECT degree_id, degree_name FROM majors";
然后将复选框的值设置为:
$out .= '<input id="cb_' .$cnt. '" class="checkChange" type="checkbox" name="check" value="'.$row['degree_id'].'" id="checky" />' .$row['degree_name']. '<br/>';
然后让我们有一个空表来显示数据:
<table id="course_table">
</table>
然后使用Ajax来调用显示:
$(document).on("change", ".checkChange", function(){ /* WHEN A CHECK BOX HAS BEEN TICKED */
var counter = 0;
/* COUNT ALL THE CHECKED CHECK BOXES */
$(".checkChange").each(function(){
if(this.checked){
++counter;
}
});
if(counter == 2){ /* IF CHECKED CHECK BOXES REACHED TWO */
/* DISABLE OTHER UNCHECKED CHECK BOXES */
$(".checkChange").each(function(){
if(!this.checked){
$(this).prop("disabled", true);
}
});
} else {
/* ENABLE ALL CHECK BOXES */
$(".checkChange").prop("disabled", false);
}
$("#course_table").empty(); /* EMPTY THE TABLE */
$('#checkboxes :checked').each(function() { /* CHECK EACH CHECKED CHECK BOXES */
var degid = $(this).val(); /* GET THE VALUE OF THE CHECKED CHECK BOX */
$.ajax({ /* CALL AJAX */
type: 'POST', /* METHOD TO USE TO PASS THE DATA */
url: 'get.php', /* FILE WHERE TO PROCESS THE DATA */
data: { 'degid' : degid }, /* DATA TO BE PASSED */
success: function(result){ /* GET THE RESULT FROM get.php */
$("#course_table").append(result); /* ADD THE COURSES RESULT TO THE HTML TABLE */
}
}); /* END OF AJAX */
}); /* END OF CHECKING EACH CHECKED CHECK BOXES */
}); /* END OF IF A CHECK BOX HAS BEEN TICKED */
您可能会注意到我们将处理get.php
中的值,因此我们创建此文件。让我们使用prepared statement:
// INCLUDE YOUR DATABASE CONNECTION
$conn = new mysqli('localhost', 'root', '', 'major_degrees');
// CHECK CONNECTION
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
if(!empty($_POST["degid"])){
$stmt = $conn->prepare("SELECT course_name FROM courses WHERE degree_id = ?"); /* PREPARE YOUR QUERY */
$stmt->bind_param("i", $_POST["degid"]); /* BIND THE SUBMITTED DATA TO YOUR QUERY; i STANDS FOR INTEGER */
$stmt->execute(); /* EXECUTE QUERY */
$stmt->bind_result($coursename); /* BIND RESULT TO THIS VARIABLE */
while($stmt->fetch()){ /* FETCH ALL RESULTS */
echo '<tr>
<td>'.$coursename.'</td>
</tr>';
}
$stmt->close(); /* CLOSE PREPARED STATEMENT */
}
/* WHAT YOU ECHO/DISPLAY HERE WILL BE RETURNED TO degree.php */