Head First PHP&MySQL study notes (2)-PHP Tutorial-php.cn

Head First PHP&MySQL study notes (2)

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Release： 2016-08-08 09:31:07

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3. Create and populate the database

1. A web application is a dynamic website designed to meet a specific goal of the user

2. In PHP code, SQL statements do not need to end with a semicolon; while MySqL A semicolon must be added to the end of each SQL statement in the terminal

3. Create a database: CREATE DATABASE database_name

Create a table: CREATE TABLE table_name(column_name1 column_type1,column_name2 column_type2,…)

Select default database: USE database_name

Show the structure of the table: DESCRIBE table_name

Delete table: DROP TABLE table_name

Delete data: DELETE FROM table_name

Use the where clause to specify the range

4. There may be objections to how to express yes/no values in MySQL. The char(1) method is very straightforward. Very efficient

5. The -> prompt indicates that you are still entering the same statement. After the statement ends and a semicolon is added, MySQL will execute the statement

6. The mysqli_fetch_array() function stores a data row in an array

7. Code example

<?php
  // addemail.php

  $dbc = mysqli_connect(&#39;localhost&#39;, &#39;root&#39;, &#39;&#39;, &#39;elvis_store&#39;)
    or die(&#39;Error connecting to MySQL server.&#39;);

  $first_name = $_POST[&#39;firstname&#39;];  // 从前台获取数据
  $last_name = $_POST[&#39;lastname&#39;];
  $email = $_POST[&#39;email&#39;];

  $query = "INSERT INTO email_list (first_name, last_name, email)  VALUES (&#39;$first_name&#39;, &#39;$last_name&#39;, &#39;$email&#39;)";
  mysqli_query($dbc, $query)          // 执行SQL语句
    or die(&#39;Error querying database.&#39;);

  echo &#39;Customer added.&#39; . $email;

  mysqli_close($dbc);
?>

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<pre name="code" class="php"><?php
&#160;&#160;// sendemail.php

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  $from = &#39;jarray@foxmail.com&#39;;
&#160; $subject = $_POST[&#39;subject&#39;];
&#160; $text = $_POST[&#39;elvismail&#39;];

&#160; $dbc = mysqli_connect(&#39;localhost&#39;, &#39;root&#39;, &#39;&#39;, &#39;elvis_store&#39;)
&#160; &#160; or die(&#39;Error connecting to MySQL server.&#39;);

&#160; $query = "SELECT * FROM email_list";
&#160; $result = mysqli_query($dbc, $query)            // 执行SQL语句
&#160; &#160; or die(&#39;Error querying database.&#39;);

&#160; while ($row = mysqli_fetch_array($result)){     // while循环条件是mysqli_fetch_array()函数的返回值
&#160; &#160; $to = $row[&#39;email&#39;];
&#160; &#160; $first_name = $row[&#39;first_name&#39;];
&#160; &#160; $last_name = $row[&#39;last_name&#39;];
&#160; &#160; $msg = "Dear $first_name $last_name,\n$text";
&#160; &#160; mail($to, $subject, $msg, &#39;From:&#39; . $from);
&#160; &#160; echo &#39;Email sent to: &#39; . $to . &#39;<br />';
  } 

  mysqli_close($dbc);
?>

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<?php
  // removeemail.php
&#160; 
&#160; $dbc = mysqli_connect(&#39;localhost&#39;, &#39;root&#39;, &#39;&#39;, &#39;elvis_store&#39;)
    or die(&#39;Error connecting to MySQL server.&#39;);

  $email = $_POST[&#39;email&#39;];

  $query = "DELETE FROM email_list WHERE email = &#39;$email&#39;";   // 删除数据库中指定条件的邮件
  mysqli_query($dbc, $query)
    or die(&#39;Error querying database.&#39;);

  echo &#39;Customer removed: &#39; . $email;

  mysqli_close($dbc);
?>

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