Chapter 8. Table Operations
THERE ARE ONLY FOUR things you can do with a set of rows in an SQL table: insert them into a table, delete them from a table, update the values in them, or query them. The unit of work is a set of whole rows inside a base table.
When you worked with file systems, access was one record at a time, then one field within a record. Since you had repeated groups and other forms of variant records, you could change the structure of each record in the file.
The mental mode in SQL is that you grab a subset as a unit, all at once, in a base table and insert, update, or delete as a unit, all at once. Imagine that you have enough computer power that you can allocate one processor to every row in a table. When you blow your whistle, ...
Get Joe Celko's SQL for Smarties, 3rd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
