PHP, as a popular programming language, is widely used in the field of Web development. Among them, PHP's PDO_PGSQL extension is a commonly used PHP extension. It provides an interactive interface with the PostgreSQL database and can realize data transmission and interaction between PHP and PostgreSQL. This article will introduce in detail how to use PHP's PDO_PGSQL extension.

1. What is PDO_PGSQL extension?

PDO_PGSQL is an extension library of PHP. It provides an interactive interface with the PostgreSQL database and can be used for data transmission and interaction between PHP and PostgreSQL. It is one of the most popular database extensions in PHP and is used to connect to PostgreSQL databases and perform operations such as querying, inserting, updating, and deleting data.

Using the PDO_PGSQL extension has many benefits, the most important of which is that it provides a safe database operation mechanism that can effectively avoid security risks such as SQL injection attacks.

2. How to install the PDO_PGSQL extension?

To use the PDO_PGSQL extension, you first need to install it into PHP. The following are the installation steps:

1. In Linux systems, use the following command to install the PostgreSQL client library:

sudo apt-get install postgresql-client libpq5 libpq-dev php-pgsql

2. In Windows systems, you can uncomment in the php.ini file The following lines:

extension=php_pdo_pgsql.dll

3. After the installation is complete, restart PHP.

3. How to connect to PostgreSQL database?

You need to use the PDO constructor to connect to the PostgreSQL database. The specific code is as follows:

try {
    $dbh = new PDO('pgsql:host=localhost;dbname=test', $user, $pass);
    foreach($dbh->query('SELECT * from users_common') as $row) {
        print_r($row);
    }
    $dbh = null;
} catch (PDOException $e) {
    print "Error!: " . $e->getMessage() . "<br/>";
    die();
}

In the above code, $user and $pass represent the user name and password of the PostgreSQL database, and host and dbname represent the username and password. The host and database name to connect to.

4. How to perform query operation?

You need to use PDO's query method to perform query operations. The specific code is as follows:

$stmt = $dbh->query('SELECT name, email FROM users_common');
while ($row = $stmt->fetch()) {
    echo $row['name'] . "    " . $row['email'] . "
";
}

In the above code, $stmt will return a result set object after receiving the query results. We can use the fetch() method to read the result set line by line and obtain the query results.

5. How to perform the insertion operation?

To perform the insertion operation, you need to use the prepare() and execute() methods of PDO. The specific code is as follows:

$stmt = $dbh->prepare("INSERT INTO users_common (name, email) VALUES (?, ?)");
$stmt->bindParam(1, $name);
$stmt->bindParam(2, $email);

$name = "張三";
$email = "zhangsan@example.com";
$stmt->execute();

$name = "李四";
$email = "lisi@example.com";
$stmt->execute();

In the above code, first use the prepare() method to preprocess the inserted SQL statement. Then use the bindParam() method to bind parameters, and finally use the execute() method to execute the SQL statement.

6. How to perform update and delete operations?

Similar to performing insert operations, performing update and delete operations also requires the use of PDO's prepare() and execute() methods. The specific code is as follows:

$stmt = $dbh->prepare("UPDATE users_common SET email=:email WHERE id=:id");
$stmt->bindParam(':email', $email);
$stmt->bindParam(':id', $id);

$email = "zhangshang@gmail.com";
$id = 1;
$stmt->execute();

$stmt = $dbh->prepare("DELETE FROM users_common WHERE id=:id");
$stmt->bindParam(':id', $id);

$id = 2;
$stmt->execute();

In the above code, first use prepare() method to prepare the SQL statement to be updated or deleted. Then use the bindParam() method to bind the parameters, and use the execute() method to execute the SQL statement.

7. Summary

This article introduces how to use PHP's PDO_PGSQL extension to connect to the PostgreSQL database and perform query, insert, update and delete operations. Using the PDO_PGSQL extension can handle database operations more safely and effectively avoid security risks such as SQL injection attacks. Although the content covered in this article is limited, it is enough to understand and master the basic usage of PDO_PGSQL.

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