On my website when a new user registers a ID is assigned to them and this ID is the primary key in my PHPMYADMIN database.
It auto_increments by one for each new user added.
Now what I want to know is how can I reset it too one without having to kill the table and bring it back.
Thanks for your support.
EDIT:
at the moment im developing a script so im testing my registration page out.
if you really must:
ALTER TABLE `TABLE_NAME` AUTO_INCREMENT =VALUE
in phpmyadmin you have table option 'operate' or 'operations'.
That's where you can reset the auto_increment value to 0
Related
I'm using an INSERT ON DUPLICATE KEY statement for my website. It's for creating news items, so I figured I could use the same MySQL command for both creating and updating news items.
However, when I use the following:
INSERT INTO table (id,title,content) VALUES(NULL,"Test","Test");
Instead of creating a new auto increment value it throws an error. However, the command works on my main development server. But not on my laptop. Both versions of MySQL are the same, the only difference being MySQL was installed manually on my server, and with WAMP on my laptop.
Are there any MySQL Variables that could be causing this?
I would suggest using INSERT INTO table (title,content) VALUES("Test","Test");
This will create a new row in the table with a new incremented ID.
Managed to solve it as best as I can.
I checked my code and found that when I inserted the empty POST'd ID was wrapping it in quotations. I've now changed it so that it puts NULL without quotations. So my query should now look like:
INSERT INTO table (id,title,content) VALUES(NULL,"test","Test")
ON DUPLICATE KEY UPDATE title=VALUES(title), content=VALUES(content);
That now works.
I think you should make query like this,
INSERT INTO table (title,content) VALUES("Test","Test");
If it still doesn't work then check if id column is set as auto-increment or not.
My db table looks like this pic. http://prntscr.com/22z1n
Recently I've created delete.php page. it works properly but when i deleted 21th user next registered user gets 24th id instead of 21.
Is it possible to put newly registered users info to first empty row? (In this situation 21th row)
In my registration form, newly registering user can write names of existing users, and be friends with them after registration. For this friendship i have another table that associates id of newly registered user and existing user.
For this purpose i'm using mysql_insert_id during registration to get id for new user. But after deletion of 21th row during nex registration process mysql_insert_id gave me number 21. but stored in 24th row. And put to associations table 21 for new user. I wanna solve this problem
When you use an autoincrement id column, the value that the next entry will be assigned will not be reduced by deleting an entry. That is not what an autoincrement column is used for. The database engine will always increment that number on a new insert and never decrement that number on a delete.
A MySQL auto_increment column maintains a number internally, and will always increment it, even after deletions. If you need to fill in an empty space, you have to handle it yourself in PHP, rather than use the auto_increment keyword in the table definition.
Rolling back to fill in empty row ids can cause all sorts of difficulty if you have foreign key relationships to maintain, and it really isn't advised.
The auto_increment can be reset using a SQL statement, but this is not advised because it will cause duplicate key errors.
-- Doing this will cause problems!
ALTER table AUTO_INCREMENT=12345;
EDIT
To enforce your foreign key relationships as described in the comments, you should add to your table definition:
FOREIGN KEY (friendid) REFERENCES registration_table (id) ON DELETE SET NULL;
Fill in the correct table and column names. Now, when a user is deleted from the registration, their friend association is nulled. If you need to reassociate with a different user, that has to be handled with PHP. mysql_insert_id() is no longer helpful.
If you need to find the highest numbered id still in the database after deletion to associate with friends, use the following.
SELECT MAX(id) FROM registration_table;
Auto increment is a sequence key that's tracked as part of the table. It does not go back when you delete a row.
Easily, no. What you can do (but I don't suggest doing) is making an SQL function to determine the lowest number that isn't currently occupied. Or you can create a table of IDs that were deleted, and get the smallest number from there. Or, and this is the best idea, ignore the gaps and realize the database is fine.
What you want to do is achievable by adding an extra column to your table called something like user_order. You can then write code to manage inserts and deletions so that this column is always sequential with no gaps.
This way you avoid the problems you could have messing around with an auto_increment column.
It's not a good practice to reset auto_increment value, but if you really need to do it, so you can:
ALTER TABLE mytable AUTO_INCREMENT = 1;
Run this query after every delete. Auto_increment value will not be set to 1, this will set the lowest possible value automatically.
This question already has answers here:
How to reset AUTO_INCREMENT in MySQL
(25 answers)
Closed 8 years ago.
I was testing some data in my tables of my database, to see if there was any error, now I cleaned all the testing data, but my id (auto increment) does not start from 1 anymore, can (how do) I reset it ?
ALTER TABLE `table_name` AUTO_INCREMENT=1
You can also do this in phpMyAdmin without writing SQL.
Click on a database name in the left column.
Click on a table name in the left column.
Click the "Operations" tab at the top.
Under "Table options" there should be a field for AUTO_INCREMENT (only on tables that have an auto-increment field).
Input desired value and click the "Go" button below.
Note: You'll see that phpMyAdmin is issuing the same SQL that is mentioned in the other answers.
ALTER TABLE xxx AUTO_INCREMENT =1;
or
clear your table by TRUNCATE
I agree with rpd, this is the answer and can be done on a regular basis to clean up your id column that is getting bigger with only a few hundred rows of data, but maybe an id of 34444543!, as the data is deleted out regularly but id is incremented automatically.
ALTER TABLE users DROP id
The above sql can be run via sql query or as php. This will delete the id column.
Then re add it again, via the code below:
ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST
Place this in a piece of code that may get run maybe in an admin panel, so when anyone enters that page it will run this script that auto cleans your database, and tidys it.
I have just experienced this issue in one of my MySQL db's and I looked at the phpMyAdmin answer here. However the best way I fixed it in phpMyAdmin was in the affected table, drop the id column and make a fresh/new id column (adding A-I -autoincrement-). This restored my table id correctly-simples! Hope that helps (no MySQL code needed-I hope to learn to use that but later!) anyone else with this problem.
I have created a PHP script and I am lacking to extract the primary key, I have given flow below, please help me in how can i modify to get primary key
I am using MySQL DB, working for Joomla, My requirement is tracking the activity like insert/update/delete on any table and store it in another audit table using triggers, i.e. I am doing Auditing. DB's table structure: Few tables dont have any PK nor auto increment key
Flow of my script is :
I fetch out all table from DB.
I check whether the table have any trigger or not.
If yes then it moves to check for next table and so on.
If it does'nt find any trigger then it creates the triggers for the table, such that,
it first checks if the table has any primary key or not(for inserting in Tracking audit table for every change made)
if it has the primary key then it uses it further in creation of trigger.
if it doesnt find any PK then it proceeds further in creating the trigger without inserting any id in audit table
Now here, My problem is I need the PK every time so that I can record the id of any particular table in which the insert/update/delete is performed, so that further i can use this audit track table to replicate in production DB..
Now as I haave mentioned earlier that I am not available with PK/auto-incremented in some table, then what should I do get the particular id in which change is done?
please guide me...GEEKS!!!
If I understand your question right, you need a unique identifier for table rows that have no primary key and no other kind of unique identifier. That's not easy to do as far as I can see. Other databases have unique Row IDs, but mySQL does not. You could use the value of every column to try and identify the row, but that is far from duplicate-safe - there could be two or more rows containing the exact same values. So I'd say, without a unique identifier, this is something that simply cannot be done.
Some ideas in this SO question:
MySQL: is there something like an internal record identifier for every record in a MySQL table?
I'm working on a script that sadly I inherited - with no commenting or anything. Argh!
For testing purposes I duplicated one of the tables in the database which had an auto-incrementing ID. When the data is saved to the database, though, the ID number just reads "0" -- which is the default for that column. I'm not sure why it's not auto increasing anymore... any thoughts? Thank you!
Are you sure you set the field in the duplicate table to auto-increment? Try running:
ALTER TABLE `duplicate_table` CHANGE `ai_key` `ai_key` INT( key_length ) NOT NULL AUTO_INCREMENT
And see if it is set or not.
Did you create the new table from scratch or as a real copy? If the column is supposed to auto increment it should be a primary (or at least a unique) key, with no default value.
Just to double check use the sql statement to show the show create table syntax for both tables and compare.
show create table <table>
It sounds like your column isn't actually auto_increment any more. This has happened to me a couple of times because there was a bug (?) in phpMyAdmin which I used to create backups: it wouldn't add the auto_increment keyword into the CREATE TABLE statements. That was a massive pain in the butt...