How to insert rows in phpMyAdmin

Question

I have a database which I've opened in phpMyAdmin. I clicked the "Insert" button, which has an icon showing one row being inserted between two others.

When I actually try to insert a row, I get the following error:

1062 - Duplicate entry '294' for key 'PRIMARY'

How do I get phpMyAdmin to insert a row (presumably by increasing all the higher-numbered rows by 1) as the icon and the term "Insert" implies? It only seems to want to "Add" a row to the end, not "Insert" it.

As I said, the icon specifically shows one row being inserted between two others, and this is what I want to do. How do I get it to do what it claims it will do?

Answer 1

First, "INSERT" is standard SQL terminology for putting something in the database; it doesn't specifically mean "putting it between two existing values". I see how the icon can be a bit confusing, but when "insertting" data there is no difference between putting something at the end or in the middle of the database. For that matter, there's no real inherent order to data stored in a database; you can select many different ways to sort it when you display the data (and phpMyAdmin generally does a good job of guessing what's reasonable), but data just exists. You can select to sort it by the primary key or alphabetically by user name or any means you wish.

Second, your primary key shouldn't change. It's the key that holds your data together; if you start changing that your references from other tables will be messed up (see below). So don't change that.

Third, if you have your primary key set up with auto_increment (the A_I checkbox in phpMyAdmin), then you shouldn't ever need to set it or worry about it yourself. It's all managed by MySQL. If you aren't happy with the order and want to move 294 to 295 so you can insert something else at 294, then your database design needs tweaking because that's not how auto_incrementing primary keys are designed to work. As a simple solution, you may wish to create another field called "sort_value" or something that you can change.

Which all brings me to the root cause of your trouble: you're trying to create a new row while reusing an existing auto_increment value, and MySQL is smart enough to know this is a bad idea.

So as I said above, changing your primary key (whether or not it's auto generated) is a bad idea, but it may not be obvious why if you only have one table. But relational databases are designed so that you can reference tables from other tables, so for instance a customer database might have a table for "customers", "products", and "purchases" where the purchases table references the primary key ID from both customers and products...imagine the carnage your data would see if you then change the value of those keys in the customer table. You'd show customers associated with some other customer's purchases. So it might not make sense in your database, but overall that's the best way to handle things.

If you really, really don't want to change your database structure, don't reference that key from any other tables, and don't want to listen to my advice, you should be able to simply turn off the auto_increment function on your primary key and reorder them however you wish.