First knowledge of MySQL database operation in PHP

Wen Yu blog 2021-01-21 23:57:20
knowledge mysql database operation php


The output text

<?php
echo "Hello World!";
?>

Connect MySql database

<?php
$servername = "localhost";
$username = " user name ";
$password = " password ";
$dbname = " Database name ";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Detection connection
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
$sql = "select * from ususer";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// Output data
while($row = $result->fetch_assoc()) {
echo "".$row["Name"]."<br>";
}
} else {
echo "0 result ";
}
// Close the connection
$conn->close();
?>

Create database

<?php
$servername = "localhost";
$username = "username";
$password = "password";
// Create connection
$conn = new mysqli($servername, $username, $password);
// Detection connection
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
// Create database
$sql = "CREATE DATABASE myDB";
if ($conn->query($sql) === TRUE) {
echo " Database created successfully ";
} else {
echo "Error creating database: " . $conn->error;
}
$conn->close();
?>

establish MySQL surface

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Detection connection
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
// Use sql Create data table
$sql = "CREATE TABLE MyGuests (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
firstname VARCHAR(30) NOT NULL,
lastname VARCHAR(30) NOT NULL,
email VARCHAR(50),
reg_date TIMESTAMP
)";
if ($conn->query($sql) === TRUE) {
echo "Table MyGuests created successfully";
} else {
echo " Error creating data table : " . $conn->error;
}
$conn->close();
?>

insert data

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Detection connection
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";
if ($conn->query($sql) === TRUE) {
echo " New record inserted successfully ";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>

Insert multiple data

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create links
$conn = new mysqli($servername, $username, $password, $dbname);
// Check links
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
$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');";
$sql .= "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('Julie', 'Dooley', 'julie@example.com')";
if ($conn->multi_query($sql) === TRUE) {
echo " New record inserted successfully ";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$conn->close();
?>

Preprocessing statement

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Detection connection
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
// Preprocessing and binding
$stmt = $conn->prepare("INSERT INTO MyGuests (firstname, lastname, email) VALUES (?, ?, ?)");
$stmt->bind_param("sss", $firstname, $lastname, $email);
// Set parameters and execute
$firstname = "John";
$lastname = "Doe";
$email = "john@example.com";
$stmt->execute();
$firstname = "Mary";
$lastname = "Moe";
$email = "mary@example.com";
$stmt->execute();
$firstname = "Julie";
$lastname = "Dooley";
$email = "julie@example.com";
$stmt->execute();
echo " New record inserted successfully ";
$stmt->close();
$conn->close();
?>

Reading data

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die(" The connection fails : " . $conn->connect_error);
}
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// Output data
while($row = $result->fetch_assoc()) {
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
}
} else {
echo "0 result ";
}
$conn->close();
?>

Where Clause

The following example will start from "Persons" Select all in the table FirstName='Peter' The line of :

<?php
$con=mysqli_connect("localhost","username","password","database");
// Detection connection
if (mysqli_connect_errno())
{
echo " The connection fails : " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT * FROM Persons
WHERE FirstName='Peter'");
while($row = mysqli_fetch_array($result))
{
echo $row['FirstName'] . " " . $row['LastName'];
echo "<br>";
}
?>

The above code will be output :

Peter Griffin

Order By key word

The following example selects "Persons" All the data stored in the table , And according to "Age" Column to sort the results :

<?php
$con=mysqli_connect("localhost","username","password","database");
// Detection connection
if (mysqli_connect_errno())
{
echo " The connection fails : " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT * FROM Persons ORDER BY age");
while($row = mysqli_fetch_array($result))
{
echo $row['FirstName'];
echo " " . $row['LastName'];
echo " " . $row['Age'];
echo "<br>";
}
mysqli_close($con);
?>

The above results will be output :

Glenn Quagmire 33
Peter Griffin 35

Update

<?php
$con=mysqli_connect("localhost","username","password","database");
// Detection connection
if (mysqli_connect_errno())
{
echo " The connection fails : " . mysqli_connect_error();
}
mysqli_query($con,"UPDATE Persons SET Age=36
WHERE FirstName='Peter' AND LastName='Griffin'");
mysqli_close($con);
?>

Delete

<?php
$con=mysqli_connect("localhost","username","password","database");
// Detection connection
if (mysqli_connect_errno())
{
echo " The connection fails : " . mysqli_connect_error();
}
mysqli_query($con,"DELETE FROM Persons WHERE LastName='Griffin'");
mysqli_close($con);
?>

Participation of this paper Tencent cloud media sharing plan , You are welcome to join us , share .

版权声明
本文为[Wen Yu blog]所创,转载请带上原文链接,感谢
https://javamana.com/2021/01/20210121234656765m.html

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