Relational Table - Sequence

Data System Architecture


A sequence is a auxiliary relational data structure that maintains a sequence.

Relational sequences are generally used to create a generated primary key via an incremental number.

Transparency usage

They may also be used transparently when a auto-increment instruction in SQL is given on a column

For example with SQlite:

  id INT autoincrement, 
  description TEXT


Database may give you the possibility to query the actual or next value of a sequence.

Example with an Oracle sequence.

select my_sequence.nextval from dual;

Database implementation

  • IDENTITY in SQL Server
  • AUTOINCREMENT in Access, SQlite

Number to text and id protection

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