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  • MySQL几个注意点

    1、在创建表、对表进行操作之前,必须首先选择数据库。通过 mysql_select_db() 函数选取数据库。当您创建 varchar 类型的数据库字段时,必须规定该字段的最大长度,例如:varchar(15)。

     1 <?php
     2 $con = mysql_connect("localhost","peter","abc123");
     3 if (!$con)
     4   {
     5   die('Could not connect: ' . mysql_error());
     6   }
     7 
     8 // Create database
     9 if (mysql_query("CREATE DATABASE my_db",$con))
    10   {
    11   echo "Database created";
    12   }
    13 else
    14   {
    15   echo "Error creating database: " . mysql_error();
    16   }
    17 
    18 // Create table in my_db database
    19 mysql_select_db("my_db", $con);
    20 $sql = "CREATE TABLE Persons 
    21 (
    22 FirstName varchar(15),
    23 LastName varchar(15),
    24 Age int
    25 )";
    26 mysql_query($sql,$con);
    27 
    28 mysql_close($con);
    29 ?>

    2、mysql_fetch_array() 函数以数组的形式从记录集返回第一行。每个随后对 mysql_fetch_array() 函数的调用都会返回记录集中的下一行。

    <?php
    $con = mysql_connect("localhost","peter","abc123");
    if (!$con)
      {
      die('Could not connect: ' . mysql_error());
      }
    
    mysql_select_db("my_db", $con);
    
    $result = mysql_query("SELECT * FROM Persons");
    
    while($row = mysql_fetch_array($result))
      {
      echo $row['FirstName'] . " " . $row['LastName'];
      echo "<br />";
      }
    
    mysql_close($con);
    ?>

    将查询结果显示在表格中。

    <?php
    $con = mysql_connect("localhost","peter","abc123");
    if (!$con)
      {
      die('Could not connect: ' . mysql_error());
      }
    
    mysql_select_db("my_db", $con);
    
    $result = mysql_query("SELECT * FROM Persons");
    
    echo "<table border='1'>
    <tr>
    <th>Firstname</th>
    <th>Lastname</th>
    </tr>";
    
    while($row = mysql_fetch_array($result))
      {
      echo "<tr>";
      echo "<td>" . $row['FirstName'] . "</td>";
      echo "<td>" . $row['LastName'] . "</td>";
      echo "</tr>";
      }
    echo "</table>";
    
    mysql_close($con);
    ?>

    3、

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  • 原文地址:https://www.cnblogs.com/iammackong/p/3381887.html
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