query1.php

<?php
include_once "conn.php";

// Start the session
session_start();

if(!isset($_GET["animalName"]) || empty($_GET["animalName"]) || !isset($_GET["animalOwner"]) || empty($_GET["animalOwner"]) || !isset($_GET["VAT"]) || empty($_GET["VAT"])){
    echo('ERROR -  All fields are mandatory.');
    echo('<br>');
    echo "<a href='index.php'> <button> Go back to homepage </button></a><br>";
}else{

    //Get the data required in homepage (animal name, owner name and client VAT)
    if(isset($_GET["animalName"])){
        $_SESSION["animalName"] = $_GET["animalName"];
        $_SESSION["ownerName"] = $_GET["animalOwner"];
        $_SESSION["VAT"] = $_GET["VAT"];		
    }

    // Store client VAT in the session (to be used in getAnimal.php)
    $_SESSION["clientVAT"] = $_GET["VAT"];

    //CHECK IF CLIENT EXISTS

    //Prepare sql query to get, from the database, the client with the VAT obtained from the homepage
    try{
        $stmt = $conn->prepare("select * from client where VAT=?;");
        $stmt->bindParam(1, $_SESSION["VAT"], PDO::PARAM_INT);
 
        $stmt->execute();

        //If the result has no rows, it means that the VAT is not in the database, so the client is not registered
        if($stmt->rowCount() == 0){
            echo "VAT not registered as client";
        } else {
            //Otherwise, request to the database the person's information using the corresponding VAT number
            try{
                $stmt = $conn->prepare("select * from person where VAT=?;");
                $stmt->bindParam(1, $_SESSION["VAT"], PDO::PARAM_INT);
                $stmt->execute();

                //Display client's info in a table
                echo "Client:";
                echo "<table border='1'><tr><th>Name</th><th>VAT</th><th>Street</th><th>City</th><th>Zip address</th></tr>";
                foreach ($stmt as $row){

                    //Store the name of the client
                    $clientName = $row["name"];

                    //Display client's name, VAT, address_street, address_city and address_zip
                    echo("<tr><th>".$row["name"]."</th>");
                    echo("<th>".$row["VAT"]."</th>");
                    echo("<th>".$row["address_street"]."</th>");
                    echo("<th>".$row["address_city"]."</th>");
                    echo("<th>".$row["address_zip"]."</th></tr>");
                }
                echo "</table><br><br><br>";
            }catch(PDOException $e){
                echo('ERROR Couldnt access person. Execute() failed: ' . $e->getMessage());
                echo('<br>');
            }

            try{
                //Get, from the database, the complete name of the owner and the animal species from the animal's name and (part of) the owner name
                $sql = "select a.name animalName, p.name personName, a.species_name speciesName from animal a
                join person p on a.name=? and a.VAT=p.VAT and p.name like ?;";
                $stmt = $conn->prepare($sql);
                $keyword = "%".$_SESSION["ownerName"]."%";
                $stmt->bindParam(1, $_SESSION["animalName"], PDO::PARAM_STR);
                $stmt->bindParam(2, $keyword, PDO::PARAM_STR);
                $stmt->execute();

                //If the result has no rows, it means that there are no correspondences between the animal name and the (portion of) owner name provided
                if($stmt->rowCount() == 0){
                    echo "There are no correspondences between animal name and owner name<br>";
                    
                    //Option to register a new animal
                    echo "Regist animal: <br>";

                    //Display form to register animal with the client as the owner and go to registanimal.php
                    ?>
                    <html>
                        <body>
                            <?php echo'<form login method="POST" action="registanimal.php"'?>
                            <label for='registerAnimalColour'>Animal colour*</label>
                            <input type='text' name='registerAnimalColour'><br>
                            <label for='registerAnimalSpecies'>Animal species*</label>
                            <input type='text' name='registerAnimalSpecies'><br>
                            <label for='registerAnimalGender'>Animal gender*</label>
                            <input type='text' name='registerAnimalGender'><br>
                            <label for='registerAnimalBirth'>Animal birth year*</label>
                            <input type='text' name='registerAnimalBirth'><br>
                            
                            <!--<button formaction="registanimal.php">Regist animal</button>-->
                            <input type='submit' name='Regist animal' value='Regist animal'>
                            <button formaction='index.php'>Go back to homepage</button>
                            <p> * - Required fields</p>
                        </body> 
                    </html>        
                <?php

                } else {
                    //Display animal name and owner name (or portion of)
                    echo "Animal name ".$animalName." with owner name ".$ownerName.":";

                    // Show a table with the animal name, species and full owner name
                    echo "<table border='1'><tr><th>Animal name</th><th>Species</th><th>Owner name</th><th>Previous consults</th></tr>";
                    foreach ($stmt as $row){

                        //Put a reference to a URL on the animal name: when clicked, execute code on getAnimal.php, passing parameters animal and owner
                        //echo "<tr><th><a href='getAnimal.php?animal=".$row["animalName"]."&owner=".$row["personName"]."'>".$row["animalName"]."</a></th>";
                        echo "<th>".$row["animalName"]."</th>";
                        echo "<th>".$row["speciesName"]."</th>";
                        echo "<th>".$row["personName"]."</th>";
                        echo "<th><a href='getAnimal.php?animal=".$row["animalName"]."&owner=".$row["personName"]."'</a> <button> View </button></th></tr>";
                    }
                    echo "</table><br><br><br>";

                    echo "<a href='index.php'> <button> Go back to homepage </button></a><br>";  
                }
            }catch(PDOException $e){
                echo('ERROR Couldnt query the database for animal-owner matches. Execute() failed: ' . $e->getMessage());
                echo('<br>');
            }
        }
    }catch(PDOException $e){
        echo('ERROR Couldnt access client. Execute() failed: ' . $e->getMessage());
        echo('<br>');
    }
}