Re: bridge tables

[Joe Celko]

Is this what you would have posted if you had bothered with DDL instead of your personal pseudo-code? Aslo, fields and columns are totally different concepts; I never heard the term "bridge table" outside of card games before.

CREATE TABLE Authors -- more than one??
(author_id INTEGER NOT NULL PRIMARY KEY,
author_name VARCHAR(25) NOT NULL,
etc.);

CREATE TABLE Books -- more than one??
(isbn CHAR(13) NOT NULL PRIMARY KEY,
book_title VARCHAR(25) NOT NULL,
etc.);

CREATE TABLE Authorship -- common name for the relationship
(author_id INTEGER NOT NULL
REFERENCES Authors(author_id)
ON DELETE CASCADE
ON UPDATE CASCADE,
isbn CHAR(13) NOT NULL
REFERENCES Books(isbn)
ON DELETE CASCADE
ON UPDATE CASCADE,
PRIMARY KEY (author_id, isbn),
author_role CHAR(3) NOT NULL, --author, co-author, contributor, editor, etc.
etc.);

>> when I enter data into the two separate tables, the identifiers do not get entered into the bridge [sic] table. <<

You have to put your work into a single transaction; insert the book data, insert yhe Authors and then insert the authorship as the last step once the two requried entities are in place. This sounds like a PHP coding problem, not SQL. Were you thinking that the relationship would appear automatically?