update cell value if value not already in - php

Question

I have to update the column File on the TABLE TEST. This column contains the files related to the row. Each file is separated by a |.
An example could be
ID NAME FILE
1 apple fruit.png | lemon.png
Now when I add a new file to the FILE column I use this query:
$link->query("UPDATE TEST SET File = CONCAT(File, '$dbfilename') WHERE id = '$p_id'")
where $dbfilename can be e.g. pineapple.jpg |
The problem is that, if $dbfilename is already on the File values, it will be added another time, resulting double.
How can I check if File contains already $dbfilename, and if yes, don't add id, or even don't execute the query?

Answer 1

This is not a good way of storing information in a database. But I'll get to that in a second. To directly answer your question, you could use this as your SQL query:
UPDATE TEST SET File = CONCAT(File, '$dbfilename')
WHERE id='$p_id'
AND File NOT LIKE '%$dbfilename%'
AND Lingua='$linguadilavoro'
However, this may cause some issues when one file pineapple.jpg and you try to add another-pineapple.jpg
Really, I think you should consider how this is a horribly bad approach to databases. Consider breaking the files off into a second table. For example:
# a table for the fruit names
CREATE TABLE fruits (
id INT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(250) NOT NULL,
UNIQUE INDEX(name)
);
# a table for file names
CREATE TABLE files (
fileid INT UNSIGNED NOT NULL DEFAULT PRIMARY KEY AUTO_INCREMENT,
fruitid INT UNSIGNED,
filename VARCHAR(250),
UNIQUE INDEX(fruitid, filename)
);
# find all of the fruits with their associated files
SELECT fruits.id, fruits.name, files.filename
FROM fruits LEFT JOIN files ON fruits.id=files.fruitid
# add a file to a fruit
INSERT INTO files (fruitid, filename)
VALUES ('$fruitID', '$filename')
ON DUPLICATE KEY UPDATE fruitid=LAST_INSERT_ID(id)

Answer 2

You will have to select out the FILE for the id.
then use explode to break it into an array
then check use in_array to determine if it should be added or not
Here is some (untested) code for guidance
$stmt = $link->query("SELECT File File from TEST WHERE id = '$p_id'");
$rec = $stmt->fetchAssoc();
$files = explode(" | ",$rec["FILE"]);
if (!in_array($dbfilename, $files)){
// add to FILE
} else {
// it's already there
}

Answer 3

I would redesign your table structure and add a new table File with the following columns instead of using a varchar field for multiple values:
Table Test
TableId, Name
Table File
FileId, TestId, FileName