PHP mysqli_get_warnings()用法及代码示例

定义和用法

如果您的最后一个 MySQLi 函数调用执行 MySQL 查询并且它生成任何错误。这mysqli_get_warnings()函数以数组的形式返回上次执行的查询产生的错误。

用法

mysqli_get_warnings($con)

参数

Sr.No	参数及说明
1	con(Mandatory) 这是一个表示与 MySQL 服务器的连接的对象。

返回值

PHP mysqli_get_warnings() 函数返回一个数组，其中包含上次查询执行期间生成的警告。

PHP版本

这个函数最初是在 PHP 版本 5 中引入的，适用于所有后续版本。

假设我们创建了一个名为 Emp 的表，如下所示 -

CREATE TABLE EMP(
   ID TINYINT,
   First_Name VARCHAR(50) Not NULL, 
   Last_Name VARCHAR(10) Not NULL, 
   Date_Of_Birth date, 
   Salary Int(255)
);

示例

以下示例演示了 mysqli_get_warnings() 函数的用法(程序风格) -

<?php
   //Creating a connection
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   //Inserting a record into the employee table
   $sql = "INSERT IGNORE into emp values(1, 'Sanjay', NULL, DATE('1981-12-05'), 2566)";
   mysqli_query($con, $sql);
   //Warnings
   $warnings = mysqli_get_warnings($con);
   print("Warning(s):"."\n");
   print_r($warnings);

   $sql = "INSERT IGNORE into emp values (15, 'Swetha', 'Yellapragada', DATE('1990-11-25'), 9986), (15, NULL, 'Prayaga', DATE('1990-11-25'), 9986)";
   mysqli_query($con, $sql);
   //Warnings
   $warnings = mysqli_get_warnings($con);
   print("\n"."Warning(s):");
   print_r($warnings);

   //Closing the connection
   mysqli_close($con);

?>

这将产生以下结果 -

Warning(s):
mysqli_warning Object
(
    [message] => Column 'Last_Name' cannot be null
    [sqlstate] => HY000
    [errno] => 1048
)

Warning(s):mysqli_warning Object
(
    [message] => Data truncated for column 'Last_Name' at row 1
    [sqlstate] => HY000
    [errno] => 1265
)

示例

以下是函数 mysqli_get_warnings() 的另一个示例 -

<?php
   //Creating a connection
   $con = mysqli_connect("localhost", "root", "password", "mydb");

   //Query to DROP an unknown table
   mysqli_query($con, "drop table if exists WrongTable");
   print("\n"."Warning(s):"."\n");
   print_r(mysqli_get_warnings($con));

   //Closing the connection
   mysqli_close($con);
?>

这将产生以下结果 -

Warning(s):
mysqli_warning Object
(
    [message] => Unknown table 'mydb.wrongtable'
    [sqlstate] => HY000
    [errno] => 1051
)

示例

也可以使用mysqli_warning类的next()函数一一检索警告，如下$minus;

<?php
   //Creating a connection
   $con = new mysqli("localhost", "root", "password", "mydb");

   //Inserting a record into the employee table
   $con -> query("INSERT IGNORE into emp values(105, NULL, 'Yellapragada', DATE('1981-12-05'), 2566)");

   if($con->warning_count){
      $w = mysqli_get_warnings($con);
      do {
         echo "Warning:$w->errno:$w->message\n";
      } while ($w->next());
   }

   //Closing the connection
   $con -> close();
?>

这将产生以下结果 -

Warning:1048:Column 'First_Name' cannot be null
Warning:1265:Data truncated for column 'Last_Name' at row 1

示例

<?php
   $servername = "localhost";
   $username = "root";
   $password = "password";
   $dbname = "mydb";
   $conn = new mysqli($servername, $username, $password, $dbname);

   if (!$conn->real_connect($servername, $username, $password, $dbname)) {
      die('Connect Error (' . mysqli_connect_errno() . ') '. mysqli_connect_error());
   }
   print("Database connected" ."\n");
   mysqli_query($conn, "CREATE TABLE sample (ID INT, Name VARCHAR(20))");
   $query = "INSERT IGNORE INTO sample (id,name) VALUES(
      1,'Rajesh Ramayan Kootrapally')";

   mysqli_query($conn, $query);
   $count = mysqli_warning_count($conn);
   print("No.Of warnings in the query:".$count."\n");

   if ($count) {
      $warnings = mysqli_get_warnings($conn);
	  print_r($warnings);
   }
   mysqli_close($conn);
   
?>

这将产生以下结果 -

Database connected
No.Of warnings in the query:1
mysqli_warning Object
(
    [message] => Data truncated for column 'Name' at row 1
    [sqlstate] => HY000
    [errno] => 1265
)