Update a row if ID exists else Insert - php

This is the code of a .php file. The column "memberid" has a unique index. When a user enters a record with an existing memberid, the record must get updated else a new row is created.
I also want to show an alert box. For test purposes I added like the way below, but it is not firing. No message is displayed.
I also want to know whether it is the right approach to handle insert/update automatically?
<META http-equiv="refresh" content="2; URL=socialprofile.html">
<?php
error_reporting(E_ALL ^ E_NOTICE);
require_once("../Lib/dbaccess.php");
//Retrieve values from Input Form
$CandidateID = $_POST["inCandidate"];
$SocialProfile = $_POST["inActivities"];
$InsertQuery = "INSERT INTO candidate_db_social (memberid, socialactivities, lastupdated) VALUES (".$CandidateID.",'".$SocialProfile."',now())";
$UpdateQuery = "UPDATE candidate_db_social SET socialactivities='".$SocialProfile."', lastupdated=now() WHERE memberid=".$CandidateID;
try
{
$Result = dbaccess::InsertRecord($InsertQuery);
}
catch(exception $ex)
{
$Result = dbaccess::InsertRecord($UpdateQuery);
echo "<script type='text/javascript'>alert('".$ex."');</script>";
}
?>

You should use the MySQL ON DUPLICATE KEY clause:
http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html
Also see REPLACE:
http://dev.mysql.com/doc/refman/5.0/en/replace.html

See the MySQL REPLACE keyword. It works exactly like INSERT, but overwrites existing records based on primary key. Read up on the details though, because it's not exactly equivalent to trying an INSERT, followed by an UPDATE.
INSERT ... ON DUPLICATE might be what you need instead. Situations with triggers or foreign keys come to mind. Longer syntax however :)

REPLACE INTO candidate_db_social (memberid, socialactivities, lastupdated) VALUES (".$CandidateID.",'".$SocialProfile."',now())";

you can use the INSERT ... ON DUPLICATE KEY UPDATE syntax, as in:
insert into t values ('a', 'b', 'c') on duplicate key
update a='a', b='b', c='c'

use mysql
INSERT INTO table VALUES()
ON duplicate KEY UPDATE ..;
example :
http://www.mysqlperformanceblog.com/2006/05/29/insert-on-duplicate-key-update-and-summary-counters/

I usually just check for the existence of a record ID value from either the $_POST or $_GET array (depending on the situation). If a value exists and is numeric, attempt to UPDATE the row with the corresponding ID; if not perform an INSERT query.

Related

how to check mysql for duplicates with php

I need a way to check a database if a word is in it already if so then it doesn't have to be pushed to the database if the word isn't in it yet then it has to be pushed into it.
It's a MYSQL database and I have to do it in PHP this is what I got so far.
$result = array_count_values(explode(" ", $filter));
arsort($result);
foreach ($result as $word => $frequency)
{
if (!in_array($word, [" ", ""]))
query("words", "INSERT INTO Woord (woord) VALUE (?)",[$word], false);
}
query("words" "SELECT WHERE")
You have 2 options:
REPLACE
REPLACE INTO table
SET column = 'example'
This will overwrite if the record exists and if not it will create it.
INSERT IGNORE
INSERT IGNORE INTO table
SET column = 'example'
This will ignore the query if already exists and if not it will create it.
Your php query should look like this:
"INSERT IGNORE INTO ID142118_ascii.Woord (woord) VALUES (".$word.")"
put a unique constraint on the column "woord" in the table.
Then you can let your php script insert as many duplicate words as you want to, it will simply fail.
you could either add a part "ignore duplicate" in your query or just ignore the error you will get.
I thinks that will be easiest to do.
edit:
btw I can think of a lot of words containing serveral of the character you are stripping: "foto's", "zee-eend" etc
--
how to make a unique index:
ALTER TABLE asciiwoorden
ADD UNIQUE INDEX somename (Woord);

ON DUPLICATE KEY UPDATE - Condition WHERE vs CASE WHEN vs IF?

I am refering to this post. I am stuck with a problem I can't resolve. I try to insert multiple rows with a php script into a MySQL database. I don't succeed in updating the whole thing using ON DUPLICATE KEY UPDATE and using a WHERE condition (at the end of the code below) I would like to use to update only an entry has been modified recently:
// for information (used in a foreach loop):
$args[] = '("'.$row['lastname'].'", '.$row['phone'].', "'.$row['lastModification'].'")';
// then:
$stringImplode = implode(',', $args);
// Where I am stuck - WHERE statement:
$sql = $mysqli->query('INSERT INTO table_name '. (lastname, phone, timestamp) .' VALUES '.$stringImplode .'ON DUPLICATE KEY UPDATE lastname=VALUES(lastname), phone=VALUES(phone) WHERE timestamp > VALUES(lastModification);
Everything works fine except I cannot set any WHERE condition at this point that involves multiples entries. Maybe the WHERE statement in this case is not intended to refer to a condition in this statement.
I was told to try with a database procedure using a JOIN statement and a temporary table with first all my entries and then querying some conditions. But I have to admit I don't understand very well how I could leverage such a table to update an other table.
Is there an easy and lovely way to use a "CASE WHEN" or an "IF" statement in this case?
Would something like
INSERT INTO ... ON KEY DUPLICATE UPDATE lastname = VALUES(lastname), phone = VALUES(phone)
CASE WHEN (timestamp > VALUES(lastModification)) THEN do nothing ...
or
...ON KEY DUPLICATE UPDATE... IF (timestamp > VALUES(lastModification)) ...
If anyone could help me, I would be very grateful.
EDIT: Since I will have many variables, could it be used in this way:
INSERT INTO ... ON KEY DUPLICATE UPDATE
IF(timestamp > VALUES(timestamp),
(
name = VALUES(name),
number = VALUES(number),
timestamp = VALUES(timestamp)
....many other variables
),
(
name = name,
number = number,
timestamp = timestamp
....many other variables)
)
You can use simple IF function in value like this:
INSERT INTO ... ON KEY DUPLICATE UPDATE
name = VALUES(name),
number = VALUES(number),
timestamp = IF(timestamp > VALUES(timestamp), VALUES(timestamp), timestamp)
If condition is not met, it will update timestamp with the same timestamp which already exists. It does not matter, because update to same values is optimized before it is even executed, so MySQL will not make real update. You should not afraid of some performance penalty.
EDIT:
IF works likes this:
IF(condition, returned when true, returned when false)
Maybe you need to switch those two arguments to fit your condition like you want.

INSERT only if both colomns are not duplicate

DELETE FROM RelationsAuthors WHERE MainId = :MainId AND AuthorId NOT IN (:authorarray)
The above code will delete anything that is not in authorarry and where MainId equals a specific value.
After the deletion I would like to insert the values of authoarray into the database if they do not exist without getting any errors.
*with using foreach $_POST['AuthorId']:
INSERT INTO RelationsAuthors (Id,MainId,AuthorId) VALUES('',:MainId,:AuthorId)
However I would like to add to my code that I need to INSERT only WHERE (MainId = :MainId AND AuthorId = :AuthorID) does not exist. How can I do that?
First, create a unique index on the two fields so the database will prevent duplicates for you:
create unique index idx_RelationsAuthors_MainId_AuthorId on RelationsAuthors(MainId, AuthorId);
Then the insert will fail with an error if you have duplicates. You can have this error ignored in a few ways. My preferred way is:
INSERT INTO RelationsAuthors (MainId, AuthorId)
VALUES(:MainId, :AuthorId)
ON DUPLICATE KEY UPDATE MainId = VALUES(MainId);
This will specifically ignore duplicate key errors, but other problems will still generate an error (if appropriate). Note I removed the first column. I'm guessing from the syntax that it is an auto-incremented id, so you don't need to include it in the insert statement at all.

PHP MYSQL Update query

I currently have the following update statement but is there anyway that I can make it retain the current values but insert and new values that are not in the db?
If not what would be the best way to achieve this?
UPDATE INTO {refocus_candidate_category} SET canid=?, categoryid=? WHERE canid=? AND categoryid=?",array($emailCheck['id'], $id, $emailCheck['id'], $id));
Function:
$catParams = array_merge(array($emailCheck['id']), $fields['Occupation']);
$catPlaceholders = '?'.str_repeat(',?',count($fields['Occupation'])-1);
$catCheck = CMS::selectQuery("SELECT * FROM {table} WHERE canid=? AND categoryid IN (".$catPlaceholders.")", $catParams);
if($catCheck != FALSE)
{
for($i=0; $i<count($fields['Occupation']); $i++) {
$id = $fields['Occupation'][$i];
CMS::updateQuery("UPDATE INTO {table} SET canid=?, categoryid=? WHERE canid=? AND categoryid=?",array($emailCheck['id'], $id, $emailCheck['id'], $id));
}
echo 'found update';
}
ID Print
$fields['Occupation'][$i] = 1678
It's not clear to me from your question precisely what you mean, but there are a number of alternatives for inserts/updates that deal with missing or already present values.
Firstly, if you just want to insert into mysql and have it either create a new row or replace an existing row (where existing is determined by the primary key matching) use REPLACE INTO instead of INSERT INTO. REPLACE INTO tries an insert, but if the primary key already exists, it turns the query into a DELETE and then retries the INSERT.
If you want to insert a new row but leave an existing row alone if you've already got one, you can either use INSERT IGNORE INTO (which may also fail to insert if you've got your data types or column info wrong...) or INSERT INTO ... ON DUPLICATE KEY UPDATE which allows you to do much finer grained control of how you handle inserts of items that already exist.
There's other options as well, but those are probably the most relevant.

mysql_affected_rows(); does not work for checking if row exists

i am using mysql_affected_rows() to check if i have to enter new record or update existing, but the problem is if the user tries to enter exactly same data as record which already exists it runs insert into.
$result = mysql_query("update Data set Score='$score',Comment='$_POST[Comments]' where Date='$_POST[forDay_3]-$_POST[forDay_1]-$_POST[forDay_2]' AND User='$_POST[UserID]';");
$last = mysql_affected_rows();
if ($last==0) {
$result1 = mysql_query("INSERT INTO Data (User,Date,Score,Comment) VALUES ('$_POST[UserID]','$_POST[forDay_3]-$_POST[forDay_1]-$_POST[forDay_2]','$score','$_POST[Comments]')");
what should i do to avoid redundant entries
You could parse mysql_info() output (but the solution itself will be affected by race condition issue)
You could create unique key User + Date and end up with a single query using ON DUPLICATE KEY UPDATE syntax:
INSERT INTO `Data` (User,Date,Score,Comment)
('$_POST[UserID]','$_POST[forDay_3]-$_POST[forDay_1]-$_POST[forDay_2]','$score','$_POST[Comments]')
ON DUPLICATE KEY UPDATE Score='$score',Comment='$_POST[Comments]'
some solutions:
add another query to see if data exists, and then decide if you want to do some action (update/delete) or nothing.
add a 'modified' column with type "TIMESTAMP" and make it on update - CURRENT_TIMESTAMP
i'd go with first option.
btw, you should escape your post data (mysql_real_escape_string) to prevent injects or malformed query string
You may get the number of affected rows with FOUND_ROWS() instead of mysql_affected_rows(). The latter counts the not modified rows as well.
$result = mysql_query("update Data set Score='$score',Comment='$_POST[Comments]' where Date='$_POST[forDay_3]-$_POST[forDay_1]-$_POST[forDay_2]' AND User='$_POST[UserID]';");
$last = mysql_query("SELECT ROW_COUNT();");
$last = mysql_fetch_array($last);
...
Reference: http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_row-count

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