Join Bill Weinman for an in-depth discussion in this video Automating timestamps with a trigger, part of SQL Essential Training.
…Triggers may also be used to create timestamps in the…table you're triggering from, as well as in other tables.…In this example, I'll show you how to use a…trigger to create timestamps and to update a transaction log.…We'll be using the test.db database.…And I'll be copying and pasting again from our exercise…files for chapter nine, this is under 03 timestamps around line…50, we're going to start by dropping both of these tables…and recreating them and creating a third table for our log.…
And you'll notice that the customer and sale…table now have this stamped column which is text.…Dates and times are stored as text in SQL lite, and then we'll insert some…rows into the customer table with Bob,…Sally, and Fred, we're familiar with them already.…And then we're going to create this trigger.…Which I'll explain in a moment.…So I'm going to copy and paste into the SQL box here in SID and press Go.…And you notice our customer table, it doesn't have any…last order id, because we populated it with just the names.…
- Understanding SQL terminology and syntax
- Creating new tables and records
- Inserting and updating data
- Writing basic SQL queries
- Sorting and filtering
- Accessing related tables with JOIN
- Working with strings
- Finding the numeric type of a value
- Using aggregate functions and transactions
- Updating a table with triggers
- Creating views
Skill Level Beginner
Q: For Mac OS X: When I try to start the Apache Web Server from the XAMPP control panel, it doesn't start, and when I open "localhost" in my web browser, I see a white screen that says "It Works!" instead of the XAMPP page.
sudo apachectl stop
Q: I'm on a Mac, and I get an error in SID that says "attempt to write a read only database." How can I fix this?
A: This usually means that the database folder does not have sufficient permissions for writing by the web user. This can happen if you create the SQL folder new, rather than copying it from the Exercise Files. Here's how to fix this:
- Open a Finder window and Navigate to /Applications/XAMPP/htdocs/SQL
- Control-click on the SQL folder and select "Get Info" from the context menu.
- Under "Sharing and Permissions" (you may need to open the disclosure triangle), in the "everyone" row, select "Read & Write."Then you can close the Info window.
- Now repeat the process for the three *.db files inside the folder.
1. SQL Quick Start
Understanding joins2m 23s
Dates and times1m 59s
10. Subselects and Views
11. A Simple CRUD Application
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