php7 数据库操作的 方法

时间：2021-04-16 19:53:03

连接数据库的方法PHP7.0以上的:

方法一：

<?php
/* Connect to a MySQL server 连接数据库服务器 */
$link = mysqli_connect(
'localhost', /* The host to connect to 连接MySQL地址 */
'root', /* The user to connect as 连接MySQL用户名 */
'root', /* The password to use 连接MySQL密码 */
'lucax_database'); /* The default database to query 连接数据库名称*/

if (!$link) {
printf("Can't connect to MySQL Server. Errorcode: %s ", mysqli_connect_error());
exit;
}else
echo '数据库连接上了！';

/* Close the connection 关闭连接*/
mysqli_close($link);
?>

https://www.cnblogs.com/jianqingwang/p/5890111.html

方法二：

<?php
$servername = "localhost";
$username = "root";
$password = "root";

$dbname = "myDB";

// 创建连接

# Tip: 如果你使用其他端口（默认为3306），为数据库参数添加空字符串，如: new mysqli("localhost", "username", "password", "", port)
$conn = new mysqli($servername, $username, $password,$dbname);

// 检测连接
if ($conn->connect_error) {
die("连接失败: " . $conn->connect_error);
}
echo "连接成功";

$conn->close();
?>

http://www.runoob.com/php/php-mysql-connect.html

创建数据库：

方法一:

$sql = "CREATE DATABASE myDB3";
if (mysqli_query($conn, $sql)) {
echo "数据库创建成功";
} else {
echo "Error creating database: " . mysqli_error($conn);
}

方法二:

// 检测连接
if ($conn->connect_error) {
　　die("连接失败: " . $conn->connect_error);
}
echo "连接成功";

$sql = "CREATE DATABASE myDB2";
if ($conn->query($sql) === TRUE) {
　　echo "数据库创建成功";
} else {
　　echo "Error creating database: " . $conn->error;
}

http://www.runoob.com/php/php-mysql-create.html

创建表的方法：

方法一:

// 使用 sql 创建数据表
$sql = "CREATE TABLE MyGuests (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP
)";

if (mysqli_query($conn, $sql)) {
echo "数据表 MyGuests 创建成功";
} else {
echo "创建数据表错误: " . mysqli_error($conn);
}

方法二:

// 使用 sql 创建数据表
$sql = "CREATE TABLE MyGuests2 (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP
)";

if ($conn->query($sql) === TRUE) {
echo "Table MyGuests created successfully";
} else {
echo "创建数据表错误: " . $conn->error;
}

http://www.runoob.com/php/php-mysql-create-table.html

插入数据的方法:

方法一:

$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";

if (mysqli_query($conn, $sql)) {
echo "新记录插入成功";
} else {
echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

方法二:

$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";

if ($conn->query($sql) === TRUE) {
echo "新记录插入成功";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}

http://www.runoob.com/php/php-mysql-insert.html

插入多条数据的方法:

方法一:

$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('Mary', 'Moe', 'mary@example.com');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('Julie', 'Dooley', 'julie@example.com')";

if (mysqli_multi_query($conn, $sql)) {
echo "新记录插入成功";
} else {
echo "Error: " . $sql . "<br>" . mysqli_error($conn);
}

方法二：

$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('22', 'Doe', 'john@example.com');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('22', 'Moe', 'mary@example.com');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('22', 'Dooley', 'julie@example.com')";

if ($conn->multi_query($sql) === TRUE) {
echo "新记录插入成功";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}

查询数据库的方法：

方法一:

$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = mysqli_query($conn, $sql);

if (mysqli_num_rows($result) > 0) {
// 输出数据
while($row = mysqli_fetch_assoc($result)) {
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
}
} else {
echo "0 结果";
}

方法二：

$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
// 输出数据
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
}
} else {
echo "0 结果";
}

http://www.runoob.com/php/php-mysql-select.html

增、删、改、查 都是使用 mysqli_query() 函数

增：http://www.runoob.com/php/php-mysql-insert.html

删：http://www.runoob.com/php/php-mysql-delete.html

改: http://www.runoob.com/php/php-mysql-update.html

查: http://www.runoob.com/php/php-mysql-select.html

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