Hi folks. I'm trying to model a vehicle compound structure and have the following:
Four seperate compounds, North, East, South and West, Each compound has a number of rows with Labels fastened to the fences As the compounds are not perfect rectangles, the rows are of differing lengths. I have tables for the compounds and rows, but can't work out how to set the constraints on the bays table - a seperate table while development takes place, merged with our existing stock table eventually; I've managed to add the constraint to prevent compound_bay records being created for compound rows that do not exist, My question is, how do I prevent a record being created for a bay higher than than the length of the row, i.e. > 20 in North row A or > 40 in East row A? -- list of available compounds create table compounds ( co_id int4 primary key, co_name varchar(80) ); -- description of rows per compound create table compound_rows ( co_id int4 references compounds(co_id), cr_id int4 not null, cr_label varchar(5) not null, cr_sequence int4 not null, cr_length int4, primary key (co_id, cr_id) ); create unique index "compound_rows_sequence_index" on compound_rows using btree (co_id, cr_sequence); create unique index "compound_rows_label_index" on compound_rows using btree (co_id, cr_label); COPY compounds (co_id,co_name) from stdin; 1 North 2 East 3 South 4 West \. COPY compound_rows (co_id,cr_id,cr_label,cr_sequence,cr_length) from stdin; 1 1 A 10 20 1 2 B 20 20 1 3 C 30 25 1 4 D 40 25 2 1 A 10 40 2 2 B 20 40 2 3 C 30 45 2 4 D 40 45 \. -- link from stock table one bay per vehicle create table compound_bays ( st_VIN varchar(17) primary key references stock (st_VIN), co_id int4 not null, cr_id int4 not null, cb_id int4 not null ); alter table compound_bays add constraint compound_bays_row_check foreign key (co_id, cr_id) references compound_rows(co_id,cr_id); -- Gary Stainburn This email does not contain private or confidential material as it may be snooped on by interested government parties for unknown and undisclosed purposes - Regulation of Investigatory Powers Act, 2000 -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql
