Primary Key

[SirChick]

Hey guys quick question,

 

Is there way to always make sure inserting new rows take a unique number in the database but not necessarily doing an "auto increment"

 

Because say the 3rd row was deleted that leaves ID 3 available.. then i would rather the next newest insert to take ID 3 rather than the one at the very end.. which is what happens using auto increment.. how is this done?

[toplay]

No there's no way that I know of unless you specify the unique data yourself.

 

There's been many threads discussing this very topic...you might want to search this forum.

 

But ask yourself, what does it matter that ID 3 is not used and the next available one is used instead?

 

A technique sometimes utilized is that a column is used to identify whether the row is considered deleted or not and the application being developed looks at that column value.  That way ID row 3 is never actually deleted but simply marked as deleted.

 

Also, depending on the application being developed, sometimes the requirement is that nothing should ever be delete for history or accounting sake.

[SirChick]

the main reason was two things..

 

if id 3 is available the only amount of added data added to that column is 3 rather than it being at the end which would become 13442233

 

which means more data on the database.

 

Secondly users use this ID to regocnise themselves in the game. So the higher the number it becomes the harder it becomes to remember their ID.

 

you make a good point with the history thing though.

[fenway]

the main reason was two things..

 

if id 3 is available the only amount of added data added to that column is 3 rather than it being at the end which would become 13442233

 

which means more data on the database.

 

Secondly users use this ID to regocnise themselves in the game. So the higher the number it becomes the harder it becomes to remember their ID.

 

you make a good point with the history thing though.

You should NEVER re-use IDs... space is not the issue, if you want you can give your users a username to remember.

[toplay]

Secondly users use this ID to regocnise themselves in the game. So the higher the number it becomes the harder it becomes to remember their ID.

 

If someone had previously used ID # 3, then you would not want to reissue that number to someone else.

 

Save yourself the time and headache and never delete or assign the same primary key to more than one person.

 

[SirChick]

Oh ok. is there any reason as to why though ?

[fenway]

Oh ok. is there any reason as to why though ?

The same reason they don't re-use social security numbers.

[TheFilmGod]

Mysql is a database. It is meant to use a lot of space.

 

Primary key is to be considered "unique." Given out once, maybe deleted - but never reused.

 

I recommend giving users a username instead of an id. Sounds pretty harsh for the users...

[toplay]

Oh ok. is there any reason as to why though ?

 

I thought it would be obvious. Read fenway's, and TheFilmGod's answers.

 

 

The same reason they don't re-use social security numbers.

 

LOL

[roopurt18]

SirChick, if an integer uses 4 bytes, then it uses 4 bytes, regardless of if you have 1, 2, or 154000 stored in it.