I'm running my DB on MYSQL community version 8.0.20. I want to reset a column's autoincrement value back to 1. I looked around and tried doing this
ALTER TABLE table_name AUTO_INCREMENT = value;
but it didn't work. I read that there's no actual way to reset the autoincrement value and that makes sense as it would affect data integrity. But I wanted to use this for a table that has no dependencies at all. How can I reset the value? I was thinking of dropping and recreating the table exactly as it is with all of it's columns and types (I don't need to retain the records)
Is there really a way to reset the auto increment value directly? If not, what is the easiest way I can drop and recreate the table in MYSQL Workbench.
Related
I am faced with a scenario where I would like to remove all existing data from one of my tables and then reuse the table again and fill it with new data.
My Question: Should I destroy/recreate the exact same table to do this? Or is there an easier way? -Side Note: I am storing user id's and would like for the id's to be set back again as opposed to continuing at the number in which last data was stored.
I'm using PhpMyAdmin.
If you use TRUNCATE TABLE.
TRUNCATE TABLE empties a table completely. Logically, this is equivalent to a DELETE statement that deletes all rows, but there are practical differences under some circumstances.
...
it resets any AUTO_INCREMENT counter to zero
So if you want to keep the counter use DELETE FROM
If you delete all rows in the table with DELETE FROM tbl_name (without a WHERE clause) in autocommit mode, the sequence starts over for all storage engines except InnoDB and MyISAM.
You can also look here: How to prevent mySQL from resetting auto increment value?
You have to truncate your table, see documentation here: https://dev.mysql.com/doc/refman/5.0/en/truncate-table.html
In phpmyadmin there's a button in the table list called: Empty
I have recently installed a new computer with Percona Server 5.6 instead of MySQL 5.6, and using InnoDB/XtraDB mostly, FWIW. The database I'm working on is merely a testing ground, but I have 1 issue: after I add a column to a table (or even remove one), I usually forget to INSERT or otherwise change another table's data, which keeps track of what column names are in which table; each table has ASCII name along with a number, and this number is the only difference between table names for simplicity. So, is there a way to auto-update the "relation" table so that the column name and table's number are added or changed, instead of using a cronjob ?
Now that I think, I could DROP that table and use information_schema instead ...
EDIT 0: Don't let the above realization stop you; it's just good to know if this is possible before going for a possible other way.
Yes, relying on the 'INFORMATION_SCHEMA.COLUMNS' may be best.
Unfortunately mysql does not support DDL TRIGGER events, as this would be what you are looking for.
triggers allow you to perform many SQL and procedural operations before insertion, update or deletion of rows in a specific table. However to the best of my knowledge - and I would be stoked if I were wrong - you cant set TRIGGER events on DDL statements like ALTER and DROP TABLE...
However still take the time to learn about triggers - they save a lot of time by eliminating the need for cronjobs and external updates for things like aggregate values.
https://dev.mysql.com/doc/refman/5.6/en/trigger-syntax.html
I am inserting some data to a database and I have an id column which has auto increment. I updated my xampp server yesterday and now the auto increment is starting from 4, 3, 5 in different tables. It used to work fine before. I did not delete any rows from the table it just starts from those numbers. What is wrong?
ALTER TABLE tablename AUTO_INCREMENT = 1
This will reset your auto increment to start from 1
If you really want to reset this, in phpMyAdmin, open this table, go to Operations and change the value for AUTO_INCREMENT.
You can reset your auto increment ID from the following Command:
ALTER TABLE TABLE_NAME AUTO_INCREMENT = 1;
This will start from 1.
OR
go to LOCALHOST/PHPMYADMIN enter:
select your DB
after choose the specific table than go to Operations an set a number to the Auto increment.
If you really want to reset this, in phpMyAdmin, open this table, go to Operations and change the value for AUTO_INCREMENT.----- this is working for me, i have just done this,
This can be a consequence of using a Galera cluster. By default, it will automatically adjust the auto_increment_increment and auto_increment_offset variables according to the size of the cluster, and when the cluster size changes. This avoids replication conflicts due to auto_increment.
The short answer is not to depend on auto_increment numbers being subsequent, without gaps.
We are using in-memory tables in MySQL with an auto-incremented primary key.
After restarting MySQL the in-memory tables are emptied as expected.
However we would like to keep the auto increment value, so that the next inserted row will have the ID after the one that was used in the last session.
Is that possible?
After the restart you can use this statement to change the next value to use for AUTO_INCREMENT columns.
ALTER TABLE mytable AUTO_INCREMENT = new_value;
The CREATE TABLE syntax is similar, but since memory tables are recreated after the restart, it won't be much use to you.
If the timing of this call is important I would recommend adding it to the startup script; I wouldn't know any other way.
We could not use the ALTER TABLE statement because a function was necessary to calculate the initial auto increment.
The solution was to:
my.cnf file was changed, after the header [mysqld] we added init-file = [file_path]
The file would execute a insert on the table with a dummy value (e.g. INSERT INTO mytable(id) VALUES (UNIX_TIMESTAMP()). After this, the line can be deleted if wished.
I am using MySql for my database. I have found how to set a column's starting autoincrement value when creating a table, but I need to know how to set a new starting value for an existing column. What does the liquibase script look like to do that?
The MySQL syntax is pretty straightforward:
ALTER TABLE mytable AUTO_INCREMENT = val ;
(Note that this is really a table attribute, not a column attribute. There can be only one column in a table declared to be AUTO_INCREMENT.)
This syntax isn't supported in SQL Server or Oracle; Oracle doesn't even have a concept of an "auto_increment" column, apart from a SEQUENCE object and a TRIGGER. SQL Server calls it an IDENTITY property. So I don't know how this statement would be represented in "liquibase" syntax, other than specifying that this statement is native MySQL syntax.
You can use addAutoIncrement (http://www.liquibase.org/documentation/changes/add_auto_increment.html) to change your existing AUTO_INCREMENT column.
Don't forget to specify columnDataType in the addAutoIncrement.
I used this yesterday for our project and it worked (for MySQL).