How to implement simple insert operation in php?

As a popular programming language, one of the most widely used applications of PHP in Web development is to implement database operations. The insertion operation is one of the most basic and common operations in database operations. In PHP, it is not difficult to implement the insertion operation. You only need to follow the following steps to achieve it.

1. Prepare the database

First, we need to connect to the database in PHP and ensure that our PHP code can successfully read and write through the database. Connecting to the database requires using one of the mysqli or PDO extension libraries provided with PHP.

mysqli extension library sample code:

// 假设连接到本地数据库，用户名为 root，密码为空
$mysqli = new mysqli("localhost", "root", "");
if ($mysqli->connect_errno) {
    die("连接失败：".$mysqli->connect_error);
}
// 选择数据库
$mysqli->select_db("test");

PDO extension library sample code:

// 假设连接到本地数据库，用户名为 root，密码为空
$dsn = "mysql:host=localhost;dbname=test;charset=utf8";
$username = "root";
$password = "";
try {
    $pdo = new PDO($dsn, $username, $password);
}
catch(PDOException $e) {
    die("连接失败：".$e->getMessage());
}

2. Write the SQL statement for the insertion operation

Next, we You need to write a SQL statement to implement the insert operation. The syntax of the SQL statement is as follows:

INSERT INTO table_name (col1, col2, col3, ...) VALUES (val1, val2, val3, ...)

Among them, table_name is the name of the table to be inserted into the data, col1, col2, col3, etc. are the column names to be inserted into the data, and val1, val2, val3, etc. are the corresponding columns. Insert value. It should be noted that the inserted value must match the data type of the column.

The following is a simple SQL statement example:

INSERT INTO users (name, age, sex) VALUES ('Tom', 26, '男')

The above SQL statement will insert a record in the users table, whose name field value is Tom, age field value is 26, and sex field value For men.

3. Implement the insert operation through PHP code

With the database connection and SQL statement, we can implement the insert operation through PHP code. In order to execute SQL statements correctly, we need to use the relevant methods provided by the PHP extension library.

For the mysqli extension library, we can use the mysqli_query method:

// 插入数据
$sql = "INSERT INTO users (name, age, sex) VALUES ('Tom', 26, '男')";
if ($mysqli->query($sql) === TRUE) {
    echo "插入成功！";
} else {
    echo "插入失败：".$mysqli->error;
}

For the PDO extension library, we can use the PDO::query method:

// 插入数据
$sql = "INSERT INTO users (name, age, sex) VALUES ('Tom', 26, '男')";
if ($pdo->query($sql)) {
    echo "插入成功！";
} else {
    echo "插入失败：".$pdo->errorInfo()[2];
}

The above code will insert Information about success or insertion failure is output to the page.

4. Extension of insertion operation

The above code implements a simple insertion operation. In actual use, we usually need to insert multiple records, and when inserting data, we need to judge based on conditions, etc. At this time, we need to expand the insertion operation.

1. Insert multiple pieces of data

To insert multiple pieces of data, you can use multiple VALUES clauses in the SQL statement, as shown below:

INSERT INTO users (name, age, sex) VALUES
    ('Tom', 26, '男'),
    ('Lily', 24, '女'),
    ('Jack', 30, '男')

Of course, we can also implement loop insertion operations.

2. Judge based on conditions when inserting data

Sometimes, we need to perform the insertion operation according to certain conditions. At this time, we need to use a conditional judgment statement, as shown below:

// 判断是否存在指定的记录
$sql = "SELECT * FROM users WHERE name = 'Tom'";
$result = $mysqli->query($sql);
if ($result->num_rows > 0) {
    echo "Tom 已存在！";
} else {
    // 插入数据
    $sql = "INSERT INTO users (name, age, sex) VALUES ('Tom', 26, '男')";
    if ($mysqli->query($sql) === TRUE) {
        echo "插入成功！";
    } else {
        echo "插入失败：".$mysqli->error;
    }
}

The above code will query whether there is a record named Tom in the users table. If it exists, it will prompt that Tom already exists, otherwise the insertion operation will be performed.

In addition to the above extensions, we can also implement richer insertion operations, such as automatically obtaining the current time, inserting pictures, etc.

To sum up, PHP only requires a few simple steps to implement simple insertion operations. For users, they only need to make certain expansions as needed to meet actual needs. It is worth mentioning that in actual projects, data security and code robustness are equally important, so when writing insert operations, you need to pay attention to whether parameter values ​​need to be filtered, SQL injection issues, etc.

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