PHP mysqli_get_warnings() 函数

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定义和用法

如果您的上次 MySQLi 函数调用执行 MySQL 查询，并且生成了任何错误。mysqli_get_warnings() 函数以数组的形式返回上次执行的查询生成的错误。

语法

mysqli_get_warnings($con)

参数

返回值

PHP mysqli_get_warnings() 函数返回一个包含上次查询执行期间生成的警告的数组。

PHP 版本

此函数首次引入于 PHP 5 版本，并在所有后续版本中均有效。

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（过程式风格）的用法：

<?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

您还可以使用 mysqli_warning 类的 next() 函数逐个检索警告，如下所示：

<?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
)