From: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
---|---|
To: | Jon Forsyth <jon4syth(at)gmail(dot)com>, pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Renumber Primary Keys and Update the same as Foreign Keys |
Date: | 2015-06-10 23:51:33 |
Message-ID: | 5578CD85.2050901@aklaver.com |
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Thread: | |
Lists: | pgsql-sql |
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(dot)klaver(at)aklaver(dot)com
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