Question

我对从数据库以及php中的文本框中重新获取值有一个疑问。

我创建了这样的表，

id    blockid   flatno
1       1A        100
2       1B        200
3       2A        100
4       2B        200

如果我尝试再次flatno作为100插入同一个区块，则必须显示一条错误消息flatno已存在于blockid 1A如何这样做..请帮帮我..

Answer 1

我认为在您的表中不添加唯一索引，因此请添加唯一索引并插入您的数据并检查数据库错误或通过代码 $

query = mysql_query("SELECT *  FROM tablename WHERE flatno=".$flatno." AND blockid=".$blockid);
$result = mysql_num_rows($query);
if($result > 0){
  echo " The Details already exists"; 
 }

Answer 2

试试这个：

SELECT * 
FROM Table1
WHERE flatno=@flatno
AND blockid=@blockid

如果上述查询返回某些内容，则显示错误消息。

echo "Flat No. already exists in this block";

Answer 3

$query = mysql_query("SELECT *  FROM tablename WHERE flatno=".$flatno." AND blockid=".$blockid);
$result = mysql_num_rows($query);
if($result > 0){
  echo "already exists"; 
 }
else{
      //insert query
 }

Answer 4

Add unique index constraint to the table for block_no and flatno columns.  that way there will not be any duplicate combination of block_no and flatno and mysql throws error as soon as you try to insert a duplicate of this.

Alter table <tablename> add constraint UQ_FLATNO unique (block_no,flatno);

once this unique constraint is added then if you try to insert a duplicate flatno combination then the sql will throw a error.

In your query execution check can be done like this:
if (mysql_errno() == 1062) {
    echo 'duplicate key';
}

检索数据库值和php文本框值

4 个答案: