In our last episode we started building up our online bookshop database, with tables for publishers, authors, formats and books. At the moment we only have one book in there, so before we go too far, lets add a few more:
INSERT INTO `book` VALUES
( NULL, 'The Big Score', 2, 4, 1, '2007-01-01', 9781741752236, 29.95 ),
( NULL, 'Split', 3, 2, 1, '2003-01-01', 0732268133, 29.95 );
So what is this NULL thing, and why have I used it? If you remember we set the first field to an auto_increment id. Because we don't want to supply a value for this, but let the database create the next value, we need to give a value that indicates we want this to happen. For this instance, NULL is the value to use. We must supply a value because we didn't restrict our insert by supplying a …
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