[mySQL]关于add table的一个注意小事项,直接影响后续populate table

<!DOCTYPE html>  
<html lang="en">  
    <meta charset="utf-8">  
    <meta http-equiv="X-UA-Compatible" content="IE=edge">  
    <meta name="viewport" content="width=device-width, initial-scale=1">  
    <title>Add a table to database</title>  
    <link href="css/bootstrap.min.css" rel="stylesheet">  
        h1 {  
            color: purple;  
        h3 {  
            color: #42d5ce;  
        .containingDiv {  
            border: 1px solid #7c73f6;  
            margin-top: 100px;  
            border-radius: 15px;  
    <div class="container-fluid">  
        <div class="row">  
            <div class="col-sm-offset-1 col-sm-10 containingDiv">  
                <h1>Add a table to database:</h1>  
                <h3>Connect to database</h3>  
                    //mysqli_connect(host, username, password, dbname)  
                    $link = @mysqli_connect("localhost", "cdwccdwc_user", "bobo1989..", "cdwccdwc_users") or die("ERROR: Unable to connect: " . mysqli_connect_error());  
                    echo "<p>Connected successfully to the database.</p>";  
                <h3>Create table</h3>  
                    $sql = "CREATE TABLE users3(ID INT(4) NOT NULL PRIMARY KEY <span style="color:#ff0000;">AUTO_INCREMENT</span>, firstname CHAR(20) NOT NULL, lastname CHAR(20) NOT NULL, email VARCHAR(30), password VARCHAR(40))";//AUTO_INCREMENT is very important,because if not add it, you can just insert all the values only once.  
                    if(mysqli_query($link, $sql)){  
                        echo "<p>Table users created successfuly!</p>";     
                        echo "ERROR: Unable to execute $sql" . mysqli_error($link);     
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>  
    <script src="js/bootstrap.min.js"></script>  


加AUTO_INCREMENT:后续populate table 的时候可以添加任意数量的表行内容,因为entry for key "primary"在自动增加,


例如:ERROR: Unable to excecute: INSERT INTO users3 (firstname, lastname, email, password) VALUES (‘tom’, ‘cluz’, ‘tm@gmial.com’,
‘ef0c0fd6710ab42cd8595bee67c65424’). Duplicate entry ‘0’ for key ‘PRIMARY’。

IT文库 » [mySQL]关于add table的一个注意小事项,直接影响后续populate table
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