Hey how would I be able to duplicate my only auto increment key to another key, basically I want my (' id ') to display the same information on my (' user_id '), here is the code:
CREATE TABLE IF NOT EXISTS `".$db_table_prefix."users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(10) NOT NULL,
`user_name` varchar(50) NOT NULL,
`username` varchar(50) NOT NULL,
PRIMARY KEY (`id`),
KEY `user_id` (`id`)
How would I be able to input the same information from my id to my user_id?
Not sure what you mean but if you want to have the same value repeted two times in the same record It's pointless and redundant.
You can use the SQL aliases to achive what you want:
SELECT id as user_id FROM ...
If you really need to sync up the two field of your table you can do:
UPDATE table SET user_id = id WHERE user_id != id
Not sure why you would want to do this, but if you want to duplicate the information after an INSERT you would need to fetch the new ID and then perform an UPDATE
// get the newly inserted ID
$new_id = $db->insert_id;
// perform the update on the table
$db->query("UPDATE users SET user_id=".$db->escape($new_id)." WHERE id=".$db->escape($new_id));
Also, in your table definition the fields don't match: int(11) vs. int(10).
Related
I have a online page which will allow user to create an account for them in order to acceess our page.
I worry in some period, there will be a lots of user who create at the same time.
In that case, I worry my database will be clash or conflict.
Can I know is that anyway to prevent that happens?
My table as below:
CREATE TABLE `user` (
`id` int(11) NOT NULL,
`userid` varchar(30) DEFAULT NULL,
`password` varchar(20) DEFAULT NULL,
`name` varchar(40) DEFAULT NULL
)
ALTER TABLE `user`
ADD PRIMARY KEY (`id`);
ADD UNIQUE KEY `userid` (`participant_id`);
ALTER TABLE `user`
MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=1;
COMMIT;
So my id will be just number and auto increment.
userid wil be unique.
I created the page by using PHP.
And I use following insert command at my page:
do {
$query = "INSERT IGNORE INTO user(userid, password, name) VALUES ('$userid','$password','$name')";
$insert = $conn->query($query);
} while( $insert && ($conn -> affected_rows == 0) );
Are this code can work perfectly to prevent the date conflit?
Another extra question is, how about if I create another extra page which will insert information 'user' table and can I used the same code at the new page?
I try to update an existing table in mysql, but I get strange results, I explain my problem:
My table looks like this:
TABLE `myTable` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`photoName` varchar(255) COLLATE latin1_general_ci NOT NULL,
`vote` int(11) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `photoName_2` (`photoName`),
)
and im trying to use saveVote.php that look like this:
$namePhoto = $_POST['name'];
$likePhoto = $_POST['like'];
mysql_connect("host","dbUser","psw");
mysql_select_db("db_is");
mysql_query("INSERT INTO `myTable` (`photoName`,`vote`) VALUES('$namePhoto','$likePhoto') ON DUPLICATE KEY UPDATE vote = vote + 1");
the 'vote' value is updated but every time when i call the "saveVote.php", for the first time he create an empty entry in my table with only the vote value and after, each time the "saveVote.php" is called
the vote value is updated for the right photoName but the vote value for the empty entry is also updated.
Why my request created this empty entry ?
Thanks for help.
It seems like your $namePhoto = $_POST['name']; is also returning a empty value. Try this:
if(!empty($_POST['name'])){
mysql_query("INSERT INTO `myTable` (`photoName`,`vote`) VALUES('$namePhoto','$likePhoto') ON DUPLICATE KEY UPDATE vote = vote + 1");
}
Keep in mind that this is just to test. This is not a fix. You need to figure out why you are sending a empty value.
I try to insert Data in the temporary Table, but when i call select last_insert_id() it return allways the same number. I have set the autoincement setting.
In the normal Table works, but when i Copy the normal Table to a temporary Table, then i have the problem with the select last_insert_id().
This is my code:
CREATE TEMPORARY TABLE IF NOT EXISTS suchergebnisse_temp (SELECT * from suchergebnisse);
INSERT INTO suchergebnisse_temp SET datensatzid='2865', datum='2015-05-13 00:00:00', tabelle='task', sortierung1='1';
SELECT LAST_INSERT_ID();
The Normal Table:
CREATE TABLE IF NOT EXISTS `suchergebnisse` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`tabelle` varchar(100) NOT NULL DEFAULT '0',
`datensatzid` bigint(20) NOT NULL DEFAULT '0',
`datum` datetime NOT NULL,
`sortierung1` int(11) NOT NULL COMMENT 'Priorität',
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Temporäre Tabelle.';
Can you help me? Thanks :)
I forgot to add the key explicit to the temporary Table. It needs to execute the following code:
ALTER TABLE `suchergebnisse_temp`
CHANGE COLUMN `id` `id` BIGINT(20) NOT NULL AUTO_INCREMENT FIRST,
ADD PRIMARY KEY (`id`);
Because with:
CREATE TEMPORARY TABLE IF NOT EXISTS suchergebnisse_temp (SELECT * from suchergebnisse);
copys only the Field Data but not the Key Data. The Key Data must be declared separately.
I'm working on a web site where users can post articles with this table structure :
CREATE TABLE IF NOT EXISTS `articles` (
`id_articles` int(10) unsigned NOT NULL AUTO_INCREMENT,
`id_users` int(10) unsigned NOT NULL,
`articles` text NOT NULL,
PRIMARY KEY (`id_articles`),
UNIQUE KEY `id_articles` (`id_articles`),
KEY `id_users` (`id_users`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
Each user can 'like' the articles.
Is that the right way below to create a 'like table' :
CREATE TABLE IF NOT EXISTS `articles_likes` (
`id_articles` int(10) unsigned NOT NULL,
`id_users` int(10) unsigned NOT NULL,
KEY `id_articles` (`id_articles`,`id_users`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
It is correct but you will want to add separte indexes on id_articles and id_users (also you might want to name the columns 'id_article' and 'id_user' for sanity).
CREATE TABLE IF NOT EXISTS `article_likes` (
`id_article` int(10) unsigned NOT NULL,
`id_user` int(10) unsigned NOT NULL,
KEY `id_article` (`id_article`),
KEY `id_user` (`id_user`)
) ENGINE=InnoDB;
The reason you want separate indexes is because in mysql if you create an index on columns (A, B) that index will be used in queries having in the where clause column A, or columns A and B.
In your case for example if you made a query "SELECT * FROM article_likes WHERE id_user=X" this query would not use an index.
An ever better option would be to add a combined index and a separate index on the second column from the combined index. Like this:
CREATE TABLE IF NOT EXISTS `article_likes` (
`id_article` int(10) unsigned NOT NULL,
`id_user` int(10) unsigned NOT NULL,
KEY `id_article_user` (`id_article`, `id_user`),
KEY `id_user` (`id_user`)
) ENGINE=InnoDB;
This way you would have optimal performance on queries like 'WHERE id_user=X', "WHERE id_article=X', "WHERE id_article=X AND id_user=Y"
This is a valid way Chris. You can use COUNT() to match the id_articles in the articles_likes table against the current article you are viewing in articles.
$articles_id = 23;
mysql_query("SELECT COUNT(*) FROM articles_likes
WHERE id_articles = ".$articles_id);
You can also just leave COUNT() (MySQL) out and instantly know which users are the "likers" of the articles and use count() (PHP) on the returned Array to duplicate the effect of COUNT() in MySQL.
i would have a total of 3 tables. an articles table, and the user id could be a column in that for users who submit articles , but you need a separate user table since not all users will submit articles (i am assuming), and then a 3rd table for likes, that takes the primary key from users and the primary key from articles and uses them as foreign keys. so each time an article is liked, an entry is made in the 3rd table
I want to automatically delete rows when the table (shown below) gets a new insert, if certain conditions are met.
When:
There are rows referring to the same 'field' with the same 'user_id'
Their 'field', 'display' and 'search' columns are the same
Simply, when the rows would become duplicates (except the 'group_id' column) the non null 'group_id' should be deleted, otherwise a row should be updated or inserted.
Is there a way to set this up in mysql (in spirit of "ON DUPLICATE do stuff" combined with unique keys etc.), or do I have to explicitly check for it in php (with multiple queries)?
Additional info:
There should always be a row with NULL 'group_id' for every possible 'field' (there's a limited set, defined elsewhere). On the other hand there might not be one with a non null 'group_id'.
CREATE TABLE `Views` (
`user_id` SMALLINT(5) UNSIGNED NOT NULL,
`db` ENUM('db_a','db_b') NOT NULL COLLATE 'utf8_swedish_ci',
`field` VARCHAR(40) NOT NULL COLLATE 'utf8_swedish_ci',
`display` TINYINT(1) UNSIGNED NOT NULL,
`search` TINYINT(1) UNSIGNED NOT NULL,
`group_id` SMALLINT(6) UNSIGNED NULL DEFAULT NULL,
UNIQUE INDEX `user_id` (`field`, `db`, `user_id`),
INDEX `Views_ibfk_1` (`user_id`),
INDEX `group_id` (`group_id`),
CONSTRAINT `Views_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `User` (`id`) ON
UPDATE CASCADE ON DELETE CASCADE
)
COLLATE='utf8_swedish_ci'
ENGINE=InnoDB;
I think you need to revise your logic. It makes no sense to Insert a row only to delete another row. Why not just update the Group_ID field in the duplicate row to what is being inserted? Below is a rough idea of how I would go about it.
N.b. I haven't done much work with MySQL and cannot get the below to run on SQLFiddle, but based on the MySQL docs I can't work out why. Perhaps someone more versed in MySQL can correct me?
SET #User_ID = 1;
SET #db = 'db_a';
SET #Field = 'Field';
SET #Display = 1;
SET #Search = 1;
SET #Group_ID = 1;
IF EXISTS
( SELECT 1
FROM Views
WHERE User_ID = #User_ID
AND DB = #DB
AND Field = #Field
AND Group_ID IS NOT NULL
)
THEN
UPDATE Views
SET Group_ID = #Group_ID,
Display = #Display,
Search = #Search
WHERE User_ID = #User_ID
AND DB = #DB
AND Field = #Field
AND Group_ID IS NOT NULL
ELSE
INSERT INTO Views (User_ID, DB, Field, Display, Search, Group_ID)
VALUES (#User_ID, #DB, #Field, #Display, #Search, #Group_ID)
END IF;
Alternatively (and my preferred solution), add a Timestamp field to your table and create a view as follows:
SELECT v.User_ID, v.DB, v.Field, v.Display, v.Search, v.Group_ID
FROM Views v
INNER JOIN
( SELECT User_ID, DB, Field, MAX(CreatedDate) AS CreatedDate
FROM Views
WHERE Group_ID IS NOT NULL
GROUP BY User_ID, DB, Field
) MaxView
ON MaxView.User_ID = v.User_ID
AND MaxView.DB = v.DB
AND MaxView.Field = v.Field
AND MaxView.CreatedDate = v.CreatedDate
WHERE v.Group_ID IS NOT NULL
UNION ALL
SELECT v.User_ID, v.DB, v.Field, v.Display, v.Search, v.Group_ID
FROM Views v
WHERE v.Group_ID IS NULL
This would allow you to track changes to your data properly, without compromising the need to be able to view unique records.
delete group_id from Views where group_id != 'NUll'
Your question is not very good to understand, so I'm not sure this is what you want:
DELETE FROM Views WHERE # delete from the table views
group_id IS NOT NULL AND # first condition delete only rows with not null group_id
(SELECT count(*) as tot FROM Views GROUP BY group_id) = 1 # second condition count the difference in group id
If that's not what you want, please update your question with more details...