Foreign keys A foreign key is a constraint enforced using the values another table’s field. The classical example is the tables storing the addresses and cities. We can store the addresses with the city field, inline.
Being the city a duplicated value over many addresses, this will cause the table bloat by storing long strings, duplicated many and many times, alongside with the the address. Defining a table with the cities and referencing the city id in the addresses table will result in a smaller row size.
I’ve started the sixth chapter, the one on the data integrity I’ve forgotten. There are the first two parts alongside with the introduction. I’ve also updated the book on slideshare with the new cover and the last incomplete chapter for the developers. The beautiful cover is made by Chiaretta & Bon. Kudos and many thanks. I’ve also uploaded the latex sources on github for anybody to fork and review my crappy english.
The three binary formats supported by pg_dump are the custom, the directory and the tar format. The first two can be accessed randomly by the restore program and have the parallel restore support, being the best choice for having a flexible and reliable restore. Before the the 9.3 the only format supporting the parallel restore was the custom. With this version the directory format accepts the -j switch. This feature, combined with the parallel dump seen in 9.
