On 06/10/2015 04:05 PM, Jon Forsyth wrote:
> Hello all,
>
> I need to make a change to my schema such that the primary key index
> numbers would change on multiple tables which are also used as foreign
> keys in multiple tables. I want to update the foreign keys to the new
> primary key index number of each record. I would prefer to do so using
> SQL statements.
>
> My database is storing different kinds of questions in separate
> tables--1. 'essay_questions' and 2. 'oral_questions' (more question
> type tables are anticipated). To simplify relationships, I have created
> a parent table called 'questions' that will have a one-to-one
> relationship with each question type table using the same primary key on
> 'question' and 'essay_question' (same for 'question' and
> 'oral_question') for a given record. I will then associate different
> media items (videos, sound files, images) with the parent question table
> in a many-to-many relationship (many media items can belong to one
> question). As it stands, the different question tables have duplicate
> primary keys with respect to each other, so combining them into the
> parent question table will require a change to several or all primary
> keys. Additionally, I have live data where two tables 1.
> 'essay_question_response' and 2. 'oral_question_response' are associated
> in a many-to-many with their corresponding question tables which will
> need the foreign keys updated after the change to primary keys.
>
> Any suggestions?
Post the actual schema definitions here, as I not entirely following the
above. In the meantime you might to look here:
http://www.postgresql.org/docs/9.4/interactive/sql-createtable.html
Search on REFERENCES. In particular ON UPDATE CASCADE.
Could be you already have the solution in place. Seeing the schema
definitions would help us answer that.
>
> Thanks,
>
> Jon
--
Adrian Klaver
adrian.klaver@aklaver.com
