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Editorial Team
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Asked: 2026-05-25T23:51:43+00:00

I’m working on a table in a database which has a primary key field

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I’m working on a table in a database which has a primary key field with numeric int value.

CREATE TABLE 'table' (
    'primary_key_field' INT NOT NULL
    'other_fields' ....
    PRIMARY KEY ( 'primary_key_field' )
)

When I insert a new element the id value is set to auto increment.

My problem is that when I delete elements and insert new ones the order of the id values is not consecutive any more but has holes in it.

ex: if I delete elements with key field value 3 and 6 the values will be:

1,2,4,5,7,..and so on..

Is there a way to keep elements in the correct succession?

ex: so that when I delete the table element with field value 3 the element with field value 4 will automatically update its value to 3 and so on for all other elements?

Thanks in advance for help!

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1 Answer

  1. Editorial Team

    Is there any reason why you need to not have gaps in your primary key sequence? Other than serving to identify a record in the database uniquely, an autoincrement primary key serves no other function. There’s no drawbacks to allowing gaps (unless you’re worried about running out of keys, and seeing as how int gives you about 2 billion values you’re unlikely to run up against that problem), and there’s considerable drawbacks to trying to not allowing gaps. For example, you delete the record with ID 3 from your table, then insert a new record. This new record, because you’re not allowing gaps, gets an ID of 3. Now how do you know that this is the original record, or one that’s replaced another record that was deleted previously?

    This problem will only be compounded if your table’s primary key is being used as a foreign key somewhere else. Suppose you delete record 3 and replace it with something else, but there’s also an entry in another table in your database that refers to record 3. Does that record’s foreign key need to be updated to point somewhere else? Should it point to the new record 3? Should it be deleted along with the original record 3? And that’s just if you have 2 tables with 1 foreign key reference. Real world databases tend to get a lot more interdependent than that very quickly.

    There is simply no good reason for doing what you want to do.

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