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Greetings! I recently joined a company that uses a fairly small
PostGres database. I have never used PostGres before, but I am familiar
with (but not expert in) SQL Server. The PostGres database has 90 tables
(including the one I just added). When the database was originally
developed, the designer merely created tables to describe the various pieces of
the system. There was no attempt to use primary or foreign keys to
describe or enforce relationships. I would like to change this. I would
like to write a function that would add a column to a table, populate it with
the number 1 to n (where n is the number of rows in the table), make that
column the table’s primary key, create a sequence beginning with n+1, and
give the new column a default of nextval(‘new_sequence’). All
of this is, if I understand things correctly, straightforward. But what
if the table already has a primary key contraint? A few of them do, but I
believe the designer used them to enforce uniqueness, not to describe
relationships. So I would like my function to check of the target table
has a primary key constraint. If it does, that constraint should be
dropped and a new one added to ensure that the column values are unique. How
can I check for the presence of constraints inside a function? Also, can someone point me to a web resource that describes
the syntax of PostGres functions? The database I have has several
functions that I can use as examples, but I don’t have a reference book. Thank you very much. Rob Richardson RAD-CON INC. |
