GDA: empty PostgreSQL table failed workaround

[Phil Longstaff]

Mark Johnson wrote:
> Previously, I had suggested a workaround for the empty PostgreSQL slots 
> table problem.
>
> I have now tried the work-around for the empty slots table problem with 
> PostgreSQL.  The type SERIAL is simply a convenience, and not a real 
> type.  I had hoped the convenience extended to ALTER TABLE, but it 
> doesn't.  The following did not work:
>
> gnucash_db=# alter table slots alter column slot_id type serial;
> ERROR:  type "serial" does not exist
>
> However, manually creating the sequence and setting a default value 
> appear to work:
> gnucash_db=# create sequence seq_slot_id;
> CREATE SEQUENCE
> gnucash_db=# alter table slots alter column slot_id set default 
> nextval('seq_slot_id');
> ALTER TABLE
>
> and confirmed by:
> gnucash_db=# \d+ slots
>
> However, this did not work.  The logfile still indicates:
> ERROR:  null value in column "slot_id" violates not-null 
> constraint                                  STATEMENT:  INSERT INTO 
> slots (obj_guid, name, slot_type, int64_val, string_val, double_val, 
> timespec
> _val, guid_val, numeric_val_num, numeric_val_denom) VALUES 
> ('391b8b5ede0a168f59664a8de0b4587f', 'sched-xaction/account', 5, NULL, 
> NULL, NULL, '1969-12-31', 'ac336ec951601638920d70c6fd4b7119', 0, 1)
>
> Issuing the following with psql:
> select nextval('seq_slot_id');
> confirms that the sequence works and counts up.
>
> So I checked the table structure.  My default value has disappeared.  It 
> appears that this was done when I first selected to save to this db.  
> The following appears in the log file:
> NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index 
> "slots_pkey" for table "slots"
> There are similar notices for all the other tables.
>
> Additionally, this problem now shows with another table:
> ERROR:  null value in column "recurrence_id" violates not-null 
> constraint                            STATEMENT:  INSERT INTO 
> recurrences (obj_guid, recurrence_mult, recurrence_period_type, 
> recurrence_period_start) VALUES ('00000000002000e00000000000a89408', 1, 
> 'month', '2005-01-24')
>   

Saving to the db deletes all tables and then recreates them.  It 
therefore deleted the slot_id without the default value.  It wouldn't 
have touched the sequence.  I'll need to build your workaround into a 
rev and then let you try it.  There's also an argument to be made that I 
should create some test cases and set up automated tests for sqlite, 
mysql and psql.  Maybe once I'm over these initial hurdles and some 
people are working with the code.

Yes, the recurrence table would have the same problem.  All of the other 
tables are for objects which have a guid as the main reference (and 
therefore as the table's primary key).  Slots and recurrences attach to 
an object but there can be more than one attached to any object.

Phil