Paging query skills for PHP and Oracle database

Paging query skills for PHP and Oracle database

When developing a dynamic web page, if you need to display a large amount of data, you need to perform paging query. Paginated query is a technique that divides data into smaller pages so that users can browse and navigate easily. In this article, we will discuss how to implement paginated queries using PHP and Oracle database, and provide relevant code examples.

1. Preparation

Before we start, we need to make sure that we have installed and configured PHP and Oracle database. If it has not been installed, you can download it from the PHP official website and Oracle official website and install and configure it according to the official documents.

2. Database preparation
We assume that we already have a table named "users", which contains various information about users, including fields such as name, age, occupation, etc.

CREATE TABLE users (

id INT PRIMARY KEY,
name VARCHAR(100),
age INT,
occupation VARCHAR(100)

);

3. PHP code implementation
In PHP, we need to use SQL query statements to obtain paging data. Below is a sample code that shows how to implement paginated query using PHP and Oracle database.

//Connect to the database
$connection = oci_connect('username', 'password', 'localhost/XE');

//Set each The number of records displayed on the page and the current page number
$perPage = 10;
$page = isset($_GET['page']) ? $_GET['page'] : 1;

//Calculate the starting position of the query
$startFrom = ($page - 1) * $perPage;

//Construct the SQL query statement
$query = "SELECT * FROM (

SELECT u.*, ROWNUM AS rnum FROM users u
WHERE ROWNUM <= :endRow

) WHERE rnum >= :startRow";

//Prepare SQL statement
$statement = oci_parse($connection, $query);

//Binding Parameters
oci_bind_by_name($statement, ':endRow', $startFrom $perPage);
oci_bind_by_name($statement, ':startRow', $startFrom);

//Execute SQL query statement
oci_execute($statement);

//Processing query results
while ($row = oci_fetch_array($statement, OCI_ASSOC)) {

//输出结果
echo "ID: " . $row['ID'] . "<br/>";
echo "Name: " . $row['NAME'] . "<br/>";
echo "Age: " . $row['AGE'] . "<br/>";
echo "Occupation: " . $row['OCCUPATION'] . "<br/><br/>";

}

//Close the database connection
oci_close($connection);

//Generate paging links
$totalPages = ceil($totalRecords / $perPage);
for ($i = 1; $i <= $totalPages; $i ) {

echo "<a href='?page=" . $i . "'>" . $i . "</a> ";

}
?>

In the above code, we use the ROWNUM function of the Oracle database to implement paging queries. The ROWNUM function assigns a unique row number to each row, and then we set the query range based on the starting position and the number of records displayed per page.

Through the above sample code, we can implement paging queries, display the data on the web page, and provide paging navigation links for users to use.

Summary

This article introduces how to use PHP and Oracle database to implement paging query, and provides relevant code examples. Paginated query is an important technology that can improve user experience and reduce server load. I hope this article will be helpful to everyone and deepen your understanding and application of paging queries.

(Note: The above code is only a sample code. In actual development, the code may need to be appropriately modified and optimized to meet actual needs.)

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